2精编辽宁省沈阳市东北育才双语学校2020-2021学年度第一学期期末试卷八年级物理试卷
2025届辽宁省沈阳市东北育才双语学校物理八年级第一学期期末教学质量检测模拟试题含解析
2025届辽宁省沈阳市东北育才双语学校物理八年级第一学期期末教学质量检测模拟试题注意事项1．考试结束后，请将本试卷和答题卡一并交回．2．答题前，请务必将自己的姓名、准考证号用0．5毫米黑色墨水的签字笔填写在试卷及答题卡的规定位置．3．请认真核对监考员在答题卡上所粘贴的条形码上的姓名、准考证号与本人是否相符．4．作答选择题，必须用2B铅笔将答题卡上对应选项的方框涂满、涂黑；如需改动，请用橡皮擦干净后，再选涂其他答案．作答非选择题，必须用05毫米黑色墨水的签字笔在答题卡上的指定位置作答，在其他位置作答一律无效．5．如需作图，须用2B铅笔绘、写清楚，线条、符号等须加黑、加粗．一、选择题1．对于密度公式mVρ=的理解，下列说法正确的是（）A．密度ρ与物体的质量m成正比B．密度ρ与物体的体积V成反比C．密度ρ与物体的质量m和体积V都有关D．密度是物质本身的一种特性，密度ρ在数值上等于质量m与体积V的比值2．衬衣领口上标有38或41等数字，它表示衣领的周长，其单位是（）A．m B．dm C．cm D．mm3．将不同金属在同一容器中加热，让它们熔化并混合，冷凝后就可以得到合金，这是制取合金的一种方法．下表是几种金属的熔点和沸点，则下列合金中，不能用该方法制取的是A．铝镁合金B．铝铜合金C．铜铁合金D．镁铁合金4．关于质量和密度，下列说法正确的是（）A．摔碎后的玻璃质量不变，但密度变小B．同种物质的状态发生变化，质量和密度均不变C．固体的密度肯定大于液体的密度D．氧气罐中的氧气用去一半，密度减小一半5．下列估测的数据中，最接近实际的是（）A．适合人的洗澡水温为72o CB．正常人的脉搏每秒钟跳动70次C．同学们行走的速度约为10m/sD．教室门的高度约为2m6．如图所示，当用一个力F将一个气球压入水中的过程（气球不会漏气且不会爆裂），球内气体的质量和密度变化情况及杯中水的相关情况变化正确的是（）A．球内气体质量变大，密度变大；杯中水的质量不变B．球内气体质量不变，密度变小；杯中水的密度不变C．球内气体质量变小，密度不变；杯中水的体积不变D．球内气体质量不变，密度变大；杯中水面高度增加7．一种声光报警器的电路如图所示，各元件均能正常工作，对可能出现的现象描述正确的是A．灯亮，铃一定响B．铃响，灯一定亮C．灯亮，铃一定不响D．铃响，灯一定不亮8．下列数值最接近生活实际情况的是（）A．普通中学生步行的速度约为8m/sB．一名普通初中学生的质量约为1.5tC．初中物理课本的宽度约为18dmD．一个鸡蛋的质量约为45g9．如图所示，小明将一个生鸡蛋放入桌面上盛有清水的烧杯中，然后从不同的位置观察鸡蛋，不可能看到的现象是（）A．看到的鸡蛋比实际小一点B．看到的鸡蛋比实际大一点C．看到的鸡蛋都是虚像D．看到的鸡蛋比实际的浅一点10．如图是一款新型水杯，在杯的夹层中封入适量的固态物质，实现了“快速降温”和“快速升温”的功能．使用时，将水杯上下晃动几分钟，可以将100 ℃的开水降温至55 ℃左右的温水，也可以将冷水升温至55 ℃左右的温水，这款水杯被广泛称为“55°杯”．“55°杯”的工作原理是( )A．首次使用时，必须加注热水；降温时利用物质熔化吸热；升温时利用凝固放热B．首次使用时，必须加注冷水；降温时利用物质凝固放热；升温时利用熔化吸热C．首次使用时，加注冷热水均可；降温时利用物质熔化吸热；升温时利用凝固放热D．首次使用时，加注冷热水均可；降温时利用物质凝固放热；升温时利用熔化吸热11．如图所示的事例中利用声音传递能量的是A．蝙蝠靠超声波发现昆虫B．倒车雷达C．医生给病人做B超D．超声波清洗眼睛12．小军和小红骑着自行车并排沿着平直的公路向北运动，突然小军加速骑行，小红仍然按着原来的速度骑行，此时若以小军为参照物，小红的运动情况是（）A．向北运动B．向西运动C．静止D．向南运动二、填空题13．如图所示，该物体的长度是_______cm。
2020-2021学年沈阳市东北育才实验学校高三英语期末考试试卷及参考答案
2020-2021学年沈阳市东北育才实验学校高三英语期末考试试卷及参考答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AF the Art World competition.Prize -The winner of each type will get the chance to display their artworks in a week-long exhibition inChelsea,New York..Eligibility - Open to artists all over the world..Entry Fee(参赛费)-$24 for a maximum of 3 submitted(提交的)photos..Date of Exhibition - From 25thApril to 2ndMay.F the Art World is an international art competition organized by which is quite unusual, compared to other competitions. The artworks are not judged on the basis of creativity and skill. Instead, they're judged by the depth of the subject matter. The subject this year is “A Competition About Change”, where artists can try and show how they'd like to change humanity in a good way.Notes*For this competition, there are three types for submissions, namely: street art, fine art, and digital art.*Each type will have a winner as chosen by the organizers and all the winners will have the wonderful chance to exhibit their works at the Unarthodox Gallery inNew Yorkin a week-long exhibition.*All the winners will also receive 100% of the sale price when any of their artworks are sold!Winners will also be displayed on the website and the entrants' artworks will also be displayed in the opening ceremony(仪式)as well.1.What is special about F the Art World Competition?AIt is free to attend.B.It lasts for over a week.C.It is open to artists inNew York.D.It centers on the depth of the artworks.2.What will the winners get?A.Prize money.B.A chance to visit an exhibition.C.A written judgement of their artworks.D.Money from the sale of their artworks.3.Where will the entrants' artworks be shown?A.In the street.B.In the opening ceremony.C.On the website.D.At the market.BCompared to dogs, cats are often considered to be aloof（冷漠的）with respect to their human owners. It is usual for them to be indifferent（无动于衷的）when humans calltheir names. Are we sure that they don’t understand human voices at all?A recent study published in the journal of Scientific Reports suggests that we’ve been fooled. Japanese scientists found that cats can recognize their names if their owners regularly use them. In the study, scientists recruited 78 domestic cats. They played recordings of voices of their owners saying five words: the first four words were random nouns thatresembledtheir names while the final word was the cat’s name. Then they observed the cats’ responses, if there were any.Most of cats moved their ears or heads when they heard their names, while they made no response to other words. That suggested, “cats were paying attention to you, what you say and what you do,” John Bradshaw, an expert on human-animal interactions（互动）at the University of Bristol, UK, told The Times. “And cats were just as good as dogs at learning,” she added.In the study, when people called their names, cats often associated (联系) the words with rewards, such as food or play, or with “punishments” such as having a bath or going to the vet . This made cats sensitive (敏感的) to words. After the cats had been called several times, they could respond to the words. But the scientists added that while dogs have evolved（进化）to follow their owners’ orders, cats have not. Although cats appear to be distant, they do have special relationships with their owners.According to study co-author Atsuko Saito, cats have evolved not to show their emotions as a survival method. One example is illness, which they tend to hide because “in the wild, no one can rescue them” and predators (捕食性动物) are more likely to pay attention to them, Saito explained.However, technology may help bridge the communication gap between cats and us. There are now mobile apps available to explain what their meows mean. So, the next time you hear “meow, meow”,your cat may be telling you: “Hi, you haven’t cleaned my litter box recently.”4. What did the recent study find about cats?A. Cats can recognize their names.B. Cats are cleverer than dogs.C. Cats learn more slowly than dogs.D. Cats are willing to follow orders.5. What does the underlined word“resembled”in paragraph 2 probably mean?A. were limited toB. were different fromC. were similar toD. were away from6. Why do cats appear distant to their human owners?A. They associate words with punishments.B. They want to protect themselves from harm.C. They are not sensitive to the human voice.D. They don’t pay much attention to their surroundings.7. What can be inferred from the last paragraph?A. It is difficult to understand cats’ meows.B. Interaction with your cats is very important.C. Cats do have good relationships with their owners.D. We may know cats better with the help of technology.CA dog spentthe lastfour years of his life waitingat a crossroad in the Thai city ofKhon Kaenas if waiting for someone. People originally thought the dog had been abandoned, but then realized that he looked healthy, so people asked around about him. It turned out that the dog had indeed been spending most of his time around that crossroad, but a woman had been coming round regularly to bring him food and water.One day, while photographing the dog everyone called Leo, a reporter met the woman who had been taking care of him. She had come to drop off some food. After learning the story about the dog and the woman, the reporter decided to share the story on social media. The post soonwent viraland the photos of Leo got shared hundreds of times. And the photos reached the eyes of Leo’s former old owner.Nang Noi Sittisarn, a 64-year-old woman fromThailand’sRoiEtProvince, almost had a heart attack when her daughter showed her a photo of the beloved dog named BonBon she had lost during a car trip. When she learned that he had been waiting for her in the same spot for the last four years，her heart melted(融化).Auntie Noi told her daughter to drive her to where the dog was waiting. When she got there and called his name. BonBon，the poor dog started wiggling(扭动)his tailand came to her，but when she tried to take him homewith her, he was unwilling to follow. She didn’ t want to force the dog to come with her so she agreed to leave him with his new master. However, she and her daughter will come to visit him regularly.8.Why did the dog look healthy after separation from his former owner?A. He walked around the crossroad constantly.B. He was kept at a woman’s home all the time.C. A local reporter brought him food and water.D. A woman looked after him on a regular basis.9. What does the underlined phrase “went viral” in paragraph 2 probably mean?A. Changed surprisingly.B. Spread quickly.C. Appeared gradually.D. Fell directly.10. How did Nang Noi Sittisam feel about the dog's waiting for her?A. Shocked.B. Regretful.C. Touched.D. Proud.11. What can we mainly learn from the story about the dog?A. Unbelievable success is worth waiting for.B. We should adjust ourselves to environments.C. We need to learn to be faithful and thankful.D. No one knows the result until the last minuteDAccording to Oxford Dictionaries, morality means: “Principles concerning the distinction between right and wrong or good and bad behavior.” Though morality is a rather subjective subject, there are some principles that are universal across all cultures found by an Oxford University study: “help your family, help your group, return favors, be brave, obey superiors, divide resources fairly, and respect others’ property”. The fact that these morals are found across 60 cultures from around the world demonstrates that morality, though subjective, is the cornerstone of keeping our societies together. Here are some reasons to be moral: without morality, a social life is almost impossible to maintain; having a good reputation and having a clear conscience is psychologically healthy; and most philosophies regard unselfish and principled behavior as important.There is no doubt that without morals, a society cannot function effectively. A confused situation would appear, According to the Society of Morality, “We are social animals, and the actions we take-the things we do and the things we don’t do-have consequences on our environments and on the others around us. As a result, we need to be able to govern our behavior in the near term so as not to injure ourselves or our community in the longterm. This system of controlling our actions and our thoughts in order to operate in a community is what we often refer to as morality”. Therefore, we need a set of morals in order to operate within a social circle and a social environment. Acting immoral usually results in being excluded from social activities or being avoided by a society based on laws and cultural standards. Besides acting moral having a sociological need, it also has a psychological basis. Most people are concerned to some extent about their reputation. According to PsyPost, “A lot of economic models of human behavior assume that people are only rational (理性的) when they narrowly pursue their own self-interest, but history shows us that people are also tremendously concerned with being and appearing moral”. So, the fear of one’s reputation being damaged is often a strong motivator to be moral. And if someonehas been immoral,most people go out of their way to make sure no one finds out, or to correct the behavior in order to not be caught. This goes in line with conscience as well. People generally feel in a better psychological state if they feel that their conscience is clean. A dirty conscience can result in a lack of sleep, anxiety, internal stress, and even illness.On the side of philosophy, the study of ethics (伦理) comes into play. Most philosophers agree that one should rationally choose a set of standards of behavior in order to function. Though there is moral relativism, there are universal anthropological (人类学的) morals, as mentioned in the introduction. By the nature of our societies and cultures, we choose what we believe is right and wrong. But surprising, this rational behavior comes to a general agreement on morals. So, there is a fine line between moral relativism and moral absolutism. But the main thing to take away from this discussion is that philosophers generally believe that each individual has the right to rationally come up with a set of ethics to live by, and that it is healthy to do so.12. The author discusses morality (paragraph 1) in order to ________.A. explain the relationship between morality and cultureB. describe the moral rules found all around the worldC. contrast the distinction between right and wrongD. introduce the definition, principles and reasons of morality13. It can be inferred from the passage that ________.A. acting moral allows us to fit into group betterB. morality brings the system of controlling behaviorC. contrast the distinction between right and wrongD. introduce the definition, principles and reasons of morality14. Which of the following is the psychological basis for acting moral?A pursuit of self-interest. B. a clean conscience.C. The concern about reputation.D. a dirty conscience.15. What does the author advise us to do according to the last paragraph?A. To reach a general agreement on morals based on ethics.B. to carve one’s own sense of ethics to operate in this world.C. To choose between moral relativism and moral absolutism.D. To exclude philosophers’ beliefs and solution as well.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。
2020-2021学年辽宁省沈阳市东北育才实验学校(小学部)一年级(上)期末数学试卷(含答案)
2020-2021 学年辽宁省沈阳市东北育才实验学校（小学部）一年级（上）期末数学试卷一、精心比较，选一选1．（4 分）看图写数。
2．（6 分）请你在横线里填上“＜”、“＞”或“＝”。
（1）5+2 8 （2）9+1 8 （3）2+6 4+4（4）9﹣5 2+7 （5）7+4 6+4 （6）9 3+63．（2 分）18 里面有个十，个一．4．（6 分）按顺序填数。
5．（2 分）16 的个位上是，十位上是。
6．（2 分）2 个一和1 个十合起来是；13 里面有个一。
7．（ 3 分）（1）上图一共有个图形，把右边的3 个图形圈起来。
第页（共15 页） 1（2）从左数排在第，从右数排在第。
8．（2 分）比19 多1 的数是；8 比少4。
9．（4 分）横线里最大填几？＜10 18＞＜6+7二、仔细审题，做判断（每题2 分，共10 分）10．（2 分）算式9﹣2＝7 读作：2 减9 等于7。
（判断对错）11．（2 分）0 可以表示什么都没有，也可以表示开始。
（判断对错）12．（2 分）羽毛球的形状是球。
（判断对错）13．（2 分）12 前面的数是13。
（判断对错）14．（2 分）苹果和西红柿都是水果。
（判断对错）三、精心比较，选一选（每题2 分，共10 分）15．（2 分）11 和16 之间有（）个数。
A．3 B．4 C．5 D．616．（2 分）淘气有8 支铅笔，笑笑和他同样多，那么他们一共有（）支铅笔。
A．2 B．4 C．10 D．1617．（2 分）今年小红7 岁，小云9 岁，两年后，小红比小云小（）岁。
A．1 B．2 C．3 D．418．（2 分）从6 开始往后数第3 个数是（）A．7 B．8 C．9 D．10第页（共15 页） 219．（2 分）如图，☆在（）的上面。
A．B．C．D．四、认真思考，做一做（共36 分）20．（12 分）直接写得数。
（1）10﹣7＝（2）15﹣5＝（3）9+3＝（4）6+8＝（5）18﹣6＝（6）4+0＝（7）7﹣7＝（8）3+9+4＝（9）5+6＝（10）12+7＝（11）18﹣10＝（12）9+5﹣5＝21．（4 分）在横线里填上合适的数。
2020-2021学年辽宁省沈阳市沈北新区东北育才双语学校八年级(上)期末数学试卷
2020-2021学年辽宁省沈阳市沈北新区东北育才双语学校八年级（上）期末数学试卷一、选择题（本大题共40小题，共100.0分）1.下列式子从左到右的变形属于因式分解的是()A. 12ab−a2=12a(b−2a) B. x2−4x+1=x(x−4)+1C. x+1=x(1+1x) D. (a+b)(a−b)=a2−b22.将下列多项式因式分解，结果中不含有因式a+1的是()A. a2−1B. a2+aC. a2+a−2D. (a+2)2−2(a+2)+13.已知m2=4+2√3，则以下对|m|的估算正确的()A. 2<|m|<3B. 3<|m|<4C. 4<|m|<5D. 5<|m|<64.已知x3+x2+x+1=0，则x2019+x2018+x2017+⋯+x+1的值是()A. 0B. 1C. −1D. 25.实数a、b在数轴上的位置如图，则|a+b|−|a−b|等于()A. 2aB. 2bC. 2b−2aD. 2b+2a6.一个正数a的平方根是2x−3与5−x，则这个正数a的值是()A. 25B. 49C. 64D. 817.如图，在平行四边形ABCD中，EF//BC，GH//AB，EF、GH的交点P在BD上，则图中面积相等的平行四边形有()A. 3对B. 2对C. 1对D. 0对8.如图，四边形ABCD中．AC⊥BC，AD//BC，BD为∠ABC的平分线，BC=3，AC=4.E，F分别是BD，AC的中点，则EF的长为()A. 1B. 1.5C. 2D. 2.59.如图，在平面直角坐标系中，矩形OABC的顶点A、C的坐标分别为(6,0)，(0,4)，OD=5，点P在线段BC上运动，当△ODP是腰长为5的等腰三角形时，则满足条件的点P有()A. 4个B. 3个C. 2个D. 1个10.如图，已知正方形ABCD的边长为4，点M和N分别从B、C同时出发，以相同的速度沿BC、CD向终点C、D运动，连接AM、BN，交于点P，连接PC，则PC长的最小值为()A. 2√5−2B. 2C. 3√5−1D. 2√511.若一个多边形截去一个角后，变成十四边形，则原来的多边形的边数可能为()A. 14或15B. 13或14C. 13或14或15D. 14或15或1612.已知四边形ABCD的两条对角线AC与BD互相垂直，则下列结论正确的是()A. 当AC=BD时，四边形ABCD是矩形B. 当AB=AD，CB=CD时，四边形ABCD是菱形C. 当AB=AD=BC时，四边形ABCD是菱形D. 当AC=BD，AD=AB时，四边形ABCD是正方形13.如图，在Rt△ABC中，∠ABC=90°，AB=6，BC=8，∠BAC，∠ACB的平分线相交于点E，过点E作EF//BC交AC于点F，则EF的长为()A. 52B. 83C. 103D. 15414.如图，在单位为1的方格纸上，△A1A2A3，△A3A4A5，△A5A6A7，…，都是斜边在x轴上，斜边长分别为2，4，6，…的等腰直角三角形，若△A1A2A3的顶点坐标分别为A1(2,0)，A2(1,1)，A3(0,0)，则依图中所示规律，A2019的坐标为()A. (−1008,0)B. (−1006,0)C. (2,−504)D. (1,505)15. 在平面直角坐标系中，点A(1,112)，B(4,32)，若点M(a,−a)，N(a +3,−a −4)，则四边形MNBA 的周长的最小值为( )A. 10+132√2 B. 5+13√2 C. 10+132√3 D. 5+13√316. 若点P(m,1)在第二象限内，则点Q(−m,0)在( )A. x 轴正半轴上B. x 轴负半轴上C. y 轴正半轴上D. y 轴负半轴上 17. 如图，平面直角坐标系中，已知直线y =x 上一点P(1,1)，C 为y 轴上一点，连接PC ，线段PC 绕点P 顺时针旋转90°至线段PD ，过点D 作直线AB ⊥x 轴，垂足为B ，直线AB 与直线y =x 交于点A ，且BD =2AD ，连接CD ，直线CD 与直线y =x 交于点Q ，则点Q 的坐标为( )A. (52,52) B. (3,3) C. (74,74) D. (94,94)18. 一辆轿车和一辆货车分别从甲、乙两地同时出发，匀速相向而行，相遇后继续前行，已知两车相遇时轿车比货车多行驶了90千米，设行驶的时间为x(小时)，两车之间的距离为y(千米)，图中的折线表示从两车出发至轿车到达乙地这一过程中y 与x 之间的函数关系.根据图象提供的信息，下列说法正确的是( )①甲乙两地的距离为450千米；②轿车的速度为90千米/小时；③货车的速度为60千米/小时；④点C 的实际意义是轿车出发5小时后到达乙地，此时两车间的距离为300千米．A. ①②B. ①③C. ①②③D. ①②③④19.如图，已知点A的坐标为(0,1)，点B的坐标为(32,−2)，点P在直线y=−x上运动，当|PA−PB|最大时点P的坐标为()A. (2,−2)B. (4,−4)C. (52,−52)D. (5,−5)20.甲、乙两名运动员同时从A地出发前往B地，在笔直的公路上进行骑自行车训练．如图所示，反映了甲、乙两名运动员在公路上进行训练时的行驶路程S(千米)与行驶时间t(小时)之间的关系，下列四种说法：①甲的速度为40千米/小时；②乙的速度始终为50千米/小时；③行驶1小时时，乙在甲前10千米处；④甲、乙两名运动员相距5千米时，t=0.5或t=2.其中正确的个数有()A. 1个B. 2个C. 3个D. 4个21.如果二次根式√x−2有意义，那么x的取值范围是()A. x>2B. x≥2C. x≠2D. x≤222.已知a<0，b≠0，化简二次根式√−a3b的结果是()A. a√−abB. −a√−abC. a√abD. −a√ab23.函数y=√2x−1x的自变量x的取值范围是()A. x≠0B. x≠0且x≥12C. x>12D. x≥1224.化简√1−6x+9x2−(√3x−5)2，结果是()A. 6x−6B. −6x+6C. −4D. 425.如图，等腰三角形ABC的底边BC长为4，面积是16，腰AC的垂直平分线EF分别交AC，AB边于E，F点．若点D为BC边的中点，点M为线段EF上一动点，则△CDM周长的最小值为()A. 6B. 8C. 10D. 1226.如图，O是正△ABC内一点，OA=3，OB=4，OC=5，将线段BO以点B为旋转中心逆时针旋转60°得到线段BO′，下列结论：①△BO′A可以由△BOC绕点B逆时针旋转60°得到；②点O与O′的距离为4；③∠AOB=150°；④S四边形AOBO′=6+3√3；⑤S△AOC+S△AOB=6+94√3.其中正确的结论是()A. ①②③⑤B. ①②③④C. ①②③④⑤D. ①②③27.已知一个直角三角形的周长是4+√26，斜边上的中线长是2，则这个三角形的面积是()A. 5B. 52C. 54D. 128.如图，在Rt△ABC中，∠ACB=90°，AC=3，BC=4，BE平分∠ABC，CD⊥AB于D，BE与CD相交于F，则CF的长是()A. 1B. 43C. 53D. 229.如图，在Rt△ABC中，∠C=90°，AC=√3，BC=1，D在AC上，将△ADB沿直线BD翻折后，点A落在点E处，如果AD⊥ED，那么△ABE的面积是()A. 1B. √32C. 3+√33D. 1+2√3430.如图，在长方形ABCD中，AB=4，BC=8，点E是BC边上一点，且AE=EC，点P是边AD上一动点，连接PE，PC，则下列结论：①BE=3；②当AP=5时，PE平分∠AEC；③△PEC周长的最小值为15；④当AP=256时，AE平分∠BEP.其中正确的个数有()A. 4个B. 3个C. 2个D. 1个31.下列从左到右的变形中，是分解因式的是()A. a2−4a+5=a(a−4)+5B. a2−b2=(a−b)2C. a2−9b2=(a+3b)(a−3b)D. (a+b)2=a2+2ab+b232.下列各式中计算正确的是()A. √(−3)2=−3B. √49=±7C. √(−1)33=−1 D. (−√3)2=−333.若m是任意实数，则点M(5+m2,1)在第()象限．A. 一B. 二C. 三D. 四34.若a+√a2−2a+1=1，则a的取值范围是()A. a=0B. a=1C. a=0或a=1D. a≤135.以下各组数为三边的三角形中，不是直角三角形的是()A. √3+1，√3−1，2√2B. 7，24，25C. 4，7.5，8.5D. 3.5，4.5，5.536. 如图，一艘轮船位于灯塔P 的北偏东60°方向，与灯塔P 的距离为30海里的A 处，轮船沿正南方向航行一段时间后，到达位于灯塔P 的南偏东30°方向上的B 处，则此时轮船所在位置B 处与灯塔P 之间的距离为( ) A. 60海里 B. 45海里 C. 20√3海里 D. 30√3海里37. 刘老师对所在班级的全体学生进行实地家访，了解到每名学生家庭的有关信息，现从中随机抽取15名学生家庭的年收入情况，数据如下表：年收入(单位：万元) 2 2.53 4 5 9 13 家庭个数13 52211关于这名学生家庭的年收入情况，下列说法不正确的是( )A. 平均数是4万元B. 中位数是3万元C. 众数是3万元D. 极差是11万元 38. 甲、乙两车从A 城出发匀速行驶至B 城.在整个行驶过程中，甲、乙两车离开A 城的距离y(千米)与甲车行驶的时间t(小时)之间的函数关系如图所示.则下列结论：①A ，B 两城相距300千米；②乙车比甲车晚出发1小时，却早到1小时；③乙车出发后2.5小时追上甲车；④当甲、乙两车相距40千米时，t =32或t =72，其中正确的结论有( )A. 1个B. 2个C. 3个D. 4个39. 如图，点B ，C 分别在直线y =2x 和直线y =kx 上，A ，D 是x 轴上两点，若四边形ABCD 是长方形，且AB ：AD =1：3，则k 的值是( )A. 23B. 25C. 27D. 2940. 如图，正方形ABCD 中，点E 为对角线AC 上一点，EF ⊥DE 交边AB 于F ，连接DF 交线段AC 于点H ，延长DE 交边BC 于点Q ，连接QF.下列结论：①DE =EF ；②若AB =6，CQ =3，则AF =2；③∠AFD =∠DFQ ；④若AH =2，CE =4，则AB =3√2+√10；其中正确的有( )个． A. 1个 B. 2个 C. 3个 D. 4个答案和解析1.【答案】A【解析】解：A.等式由左到右的变形属于分解因式，故本选项符合题意；B.等式由左到右的变形不属于分解因式，故本选项不符合题意；C.等式由左到右的变形不属于分解因式，故本选项不符合题意；D.等式由左到右的变形属于整式乘法，不属于分解因式，故本选项不符合题意；故选：A．根据分解因式的定义逐个判断即可．本题考查了因式分解的定义，注意：把一元多项式化成几个整式的积的形式，叫因式分解，也叫分解因式．2.【答案】C【解析】【分析】本题考查了因式分解的意义与方法，熟练掌握因式分解的方法是解决问题的关键.先把各个多项式分解因式，即可得出结果．【解答】∵a2−1=(a+1)(a−1)，a2+a=a(a+1)，a2+a−2=(a+2)(a−1)，(a+2)2−2(a+2)+1=(a+2−1)2=(a+1)2，∴结果中不含有因式a+1的是选项C.故选C．3.【答案】A【解析】【分析】此题主要考查了估算无理数的大小，正确得出m的值是解题关键．直接利用完全平方公式得出m的值，进而得出答案．【解答】解：∵m2=4+2√3=(√3+1)2，∴m=±(√3+1)，∴|m|=√3+1，∵1<√3<2，∴2<|m|<3．故选：A．4.【答案】A【解析】解：∵x 3+x 2+x+1=0，∴x 2019+x 2018+x 2017+x 2016+⋯+x 4+x 3+x 2+x+1=x 2016(x 3+x 2+x+1)+⋯+(x 3+x 2+x+1)=(x 3+x 2+x+1)(x 2016+⋯+x 4+1)=0．故选：A．多项式x 2019+x 2018+x 2017+x 2016+⋯+x 4+x 3+x 2+x+1共有2020项，从第一项起每4项一组，每组都含有x 3+x 2+x+1，于是分解后得到(x 3+x 2+x+1)(x 2016+⋯+x 4+1)，然后利用整体代入的方法计算．本题考查了因式分解的应用，利用提取公因式法因式分解，渗透整体代入的思想．5.【答案】A【解析】【分析】此题考查了整式的加减，绝对值，以及实数与数轴，熟练掌握运算法则是解本题的关键.根据数轴上点的位置判断出绝对值里边式子的正负，利用绝对值的代数意义化简，去括号合并即可得到结果．【解答】解：根据数轴上点的位置得：a<0<b，且|a|<|b|，∴a+b>0，a−b<0，则原式=a+b+a−b=2a．故选A．6.【答案】B【解析】解：由正数的两个平方根互为相反数可得(2x−3)+(5−x)=0，解得x=−2，所以5−x=5−(−2)=7，所以a=72=49．故选：B．利用一个正数的两个平方根互为相反数可得到(2x−3)+(5−x)=0，可求得x，再由平方根的定义可求得a的值．本题主要考查的是平方根的定义和性质，熟练掌握平方根的定义和性质是解题的关键．7.【答案】A【解析】解：∵四边形ABCD是平行四边形，∴S△ABD=S△CBD．∵BP是平行四边形BEPH的对角线，∴S△BEP=S△BHP，∵PD是平行四边形GPFD的对角线，∴S△GPD=S△FPD．∴S△ABD−S△BEP−S△GPD=S△BCD−S△BHP−S△PFD，即S▱AEPG=S▱HCFP，∴S▱ABHG=S▱BCFE，同理S▱AEFD=S▱HCDG．即：S▱ABHG=S▱BCFE，S▱AGPE=S▱HCFP，S▱AEFD=S▱HCDG．故选：A．根据平行四边形的性质：平行四边形的对角线将平行四边形的面积平分，可推出3对平行四边形的面积相等．本题考查的是平行四边形的性质，平行四边形的一条对角线可以把平行四边形分成两个全等的三角形，可以把平行四边形的面积平分．8.【答案】A【解析】解：∵AC⊥BC，∴∠ACB=90°，∵BC=3，AC=4，∴AB=5，∵AD//BC，∴∠ADB=∠DBC，∵BD为∠ABC的平分线，∴∠ABD=∠CBD，∴∠ABD=∠ADB，∴AB=AD=5，连接BF并延长交AD于G，∵AD//BC，∴∠GAC=∠BCA，∵F是AC的中点，∴AF=CF，∵∠AFG=∠CFB，∴△AFG≌△CFB(ASA)，∴BF=FG，AG=BC=3，∴DG=5−3=2，∵E是BD的中点，∴EF=1DG=1．2故选：A．根据勾股定理得到AB=5，根据平行线的性质和角平分线的定义得到∠ABD=∠ADB，求得AB=AD=5，连接BF并延长交AD于G，根据全等三角形的性质得到BF=FG，AG=BC=3，求得DG=5−3=2，根据三角形中位线定理即可得到结论．此题考查了三角形的中位线定理，全等三角形的判定和性质，勾股定理，正确的作出辅助线是解题的关键．9.【答案】C【解析】解：由题意，当△ODP是腰长为5的等腰三角形时，有三种情况：(1)如答图①所示，PD=OD=5，点P在点D的左侧．过点P作PE⊥x轴于点E，则PE=4．在Rt△PDE中，由勾股定理得：DE=√PD2−PE2=√52−42=3，∴OE=OD−DE=5−3=2，∴此时点P坐标为(2,4)；(2)如答图②所示，OP=OD=5．过点P作PE⊥x轴于点E，则PE=4．在Rt△POE中，由勾股定理得：OE=√OP2−PE2=√52−42=3，∴此时点P坐标为(3,4)；(3)如答图③所示，PD=OD=5，点P在点D的右侧．过点P作PE⊥x轴于点E，则PE=4．在Rt△PDE中，由勾股定理得：DE=√PD2−PE2=√52−42=3，∴OE=OD+DE=5+3=8，∴此时点P坐标为(8,4)(舍弃)．综上所述，点P的坐标为：(2,4)或(3,4)；故选：C．根据当OP=OD时，以及当OD=PD时，分别进行讨论得出P点的坐标．此题主要考查了矩形的性质以及坐标与图形的性质和等腰三角形的性质，根据△ODP是腰长为5的等腰三角形进行分类讨论是解决问题的关键．10.【答案】A【解析】解：由题意得：BM=CN，∵四边形ABCD是正方形，∴∠ABM=∠BCN=90°，AB=BC=4，在△ABM和△BCN中，AB=BC，∠ABM=∠BCN，MB=CN，∴△ABM≌△BCN(SAS)，∴∠BAM=∠CBN，∵∠ABP+∠CBN=90°，∴∠ABP+∠BAM=90°，∴∠APB=90°，∴点P在以AB为直径的圆上运动，设圆心为O，运动路径一条弧BG⏜，是这个圆的1，如图所示：4连接OC交圆O于P，此时PC最小，∵AB=4，∴OP=OB=2，由勾股定理得：OC=√22+42=2√5，∴PC=OC−OP=2√5−2；故选：A．先证明△ABM≌△BCN，得出∠BAM=∠CBN，证出∠APB=90°，得出点P在以AB为直径的圆上运动，运动路径一条弧BG，连接OC交圆O于P，此时PC最小，OP=OB=2，即可求解．本题考查了正方形的性质、全等三角形的判定与性质、直角三角形斜边上的中线性质、勾股定理等知识；熟练掌握正方形的性质，证出点P在以AB为直径的圆上运动是解题关键．11.【答案】C【解析】解：如图，n边形，A1A2A3…A n，若沿着直线A1A3截去一个角，所得到的多边形，比原来的多边形的边数少1，若沿着直线A1M截去一个角，所得到的多边形，与原来的多边形的边数相等，若沿着直线A1N截去一个角，所得到的多边形，比原来的多边形的边数多1，因此将一个多边形截去一个角后，变成十四边形，则原来的四边形为13或14或15，故选：C．根据不同的截法，找出前后的多边形的边数之间的关系得出答案．考查多边形的意义，根据截线的不同位置得出不同的答案，是解决问题的关键．12.【答案】C【解析】解：A、对角线AC与BD互相垂直，AC=BD时，无法得出四边形ABCD是矩形，故此选项错误；B、当AB=AD，CB=CD时，无法得到，四边形ABCD是菱形，故此选项错误；C、当两条对角线AC与BD互相垂直，AB=AD=BC时，∴BO=DO，AO=CO，∴四边形ABCD是平行四边形，∵两条对角线AC与BD互相垂直，∴平行四边形ABCD是菱形，故此选项正确；D、当AC=BD，AD=AB时，无法得到四边形ABCD是正方形，故此选项错误；故选：C．根据平行四边形、菱形的判定与性质分别判断得出即可．此题主要考查了菱形的判定以及矩形和正方形的判定，熟练掌握相关判定是解题关键．13.【答案】C【解析】【分析】本题主要考查相似三角形的判定与性质、全等三角形的判定与性质及正方形的判定与性质，熟练掌握角平分线的性质和正方形的判定与性质、相似三角形的判定与性质是解题的关键．延长FE交AB于点D，作EG⊥BC、作EH⊥AC，由EF//BC可证四边形BDEG是矩形，由角平分线可得ED=EH=EG、∠DAE=∠HAE，从而知四边形BDEG是正方形，再证△DAE≌△HAE、△CGE≌△CHE得AD=AH、CG=CH，设BD=BG=x，则AD=AH=6−x、CG=CH=8−x，由AC=10可得x=2，即BD=DE=2、AD=4，再证△ADF∽△ABC可得DF=163，据此得出EF=DF−DE=103．【解答】解：如图，延长FE交AB于点D，作EG⊥BC于点G，作EH⊥AC于点H，∵EF//BC，∠ABC=90°，∴FD⊥AB，∵EG⊥BC，∴四边形BDEG是矩形，∵AE平分∠BAC，CE平分∠ACB，∴ED=EH=EG，∠DAE=∠HAE，∴四边形BDEG是正方形，在△DAE和△HAE中，∵{∠DAE=∠HAE AE=AE∠ADE=∠AHE，∴△DAE≌△HAE(SAS)，∴AD=AH，同理△CGE≌△CHE，∴CG=CH，设BD=BG=x，则AD=AH=6−x、CG=CH=8−x，∵AC=√AB2+BC2=√62+82=10，∴6−x+8−x=10，解得：x=2，∴BD=DE=2，AD=4，∵DF//BC，∴△ADF∽△ABC，∴AD AB =DF BC ，即46=DF 8， 解得：DF =163，则EF =DF −DE =163−2=103，故选：C ．14.【答案】A【解析】解：观察图形可以看出A 1--A 4；A 5---A 8；…每4个为一组，∵2019÷4=504 (3)∴A 2019在x 轴负半轴上，纵坐标为0，∵A 3、A 7、A 11的横坐标分别为0，−2，−4，∴A 2019的横坐标为−(2019−3)×12=−1008．∴A 2019的坐标为(−1008,0)．故选：A ．观察图形可以看出A 1--A 4；A 5---A 8；…每4个为一组，由于2019÷4=504…3，A 2019在x 轴负半轴上，纵坐标为0，再根据横坐标变化找到规律即可解答．本题考查了等腰直角三角形、点的坐标，主要是根据坐标变化找到规律，再依据规律解答．15.【答案】A【解析】解：由题意，点M 在直线y =−x 上运动，点N 在直线y =−x −1上运动，MN =√32+42=5．∵A(1,112)，B(4,32)， ∴AB =√32+42=5，观察图像可知AB =MN ，AB//MN ，∴四边形AMNB 是平行四边形，∴AM =BN ，∴四边形AMNB 的周长为10+2AM ，∴当AM ⊥直线y =−x 时，AM 的值最小，此时周长的值最小，设AM 交y 轴于T ，过点A 作AH ⊥y 轴于H ．∵∠MOT =∠MTO =∠ATH =∠TAH =45°，AH =1，∴HT =AH =1，OT =92，∴AT=√2，TM=9√24，∴AM=AT+TM=13√24，∴四边形AMNB的周长的最小值为10+13√22．故选：A．由题意，点M在直线y=−x上运动，点N在直线y=−x−1上运动，MN=√32+42=5.首先证明四边形AMNB是平行四边形，推出四边形周长=10+2AM，求出AM的最小值，可得结论．本题考查轴对称最短问题，轨迹，解直角三角形等知识，解题的关键是理解题意，灵活运用所学知识解决问题，属于中考选择题中的压轴题．16.【答案】A【解析】解：由点P(m,1)在第二象限内，得m<0，−m>0，点Q(−m,0)在x轴的正半轴上，故选：A．根据第二象限内点的横坐标小于零，纵坐标大于零，可得不等式，根据不等式的性质，可得−m的取值范围，可得答案．本题考查了点的坐标，熟记点的坐标特点是解题关键，第一象限(+,+)；第二象限(−,+)；第三象限(−,−)；第四象限(+,−)．17.【答案】D【解析】解：过P作MN⊥y轴，交y轴于M，交AB于N，过D作DH⊥y轴，交y轴于H，∠CMP=∠DNP=∠CPD=90°，∴∠MCP+∠CPM=90°，∠MPC+∠DPN=90°，∴∠MCP=∠DPN，∵P(1,1)，∴OM=BN=1，PM=1，在△MCP和△NPD中，{∠CMP=∠DNP ∠MCP=∠DPN PC=PD∴△MCP≌△NPD(AAS)，∴DN=PM，PN=CM，∵BD=2AD，∴设AD=a，BD=2a，∵P(1,1)，∴BN=2a−1，则2a−1=1，a=1，即BD=2．∵直线y=x，∴AB=OB=3，在Rt△DNP中，由勾股定理得：PC=PD=√(3−1)2+(2−1)2=√5，在Rt△MCP中，由勾股定理得：CM=√( √5)2−12=2，则C的坐标是(0,3)，设直线CD的解析式是y=kx+3，把D(3,2)代入得：k=−13，即直线CD的解析式是y=−13x+3，即方程组{ y=−13x+3 y=x得：{x=94y=94，即Q的坐标是(94,9 4 ).故选：D．过P作MN⊥y轴，交y轴于M，交AB于N，过D作DH⊥y轴，交y轴于H，∠CMP=∠DNP=∠CPD=90°，求出∠MCP=∠DPN，证△MCP≌△NPD，推出DN=PM，PN=CM，设AD=a，求出DN=2a−1，得出2a−1=1，求出a=1，得出D的坐标，在Rt△DNP中，由勾股定理求出PC=PD=√5，在Rt△MCP 中，由勾股定理求出CM=2，得出C的坐标，设直线CD的解析式是y=kx+3，把D(3,2)代入求出直线CD的解析式，解由两函数解析式组成的方程组，求出方程组的解即可．本题考查了用待定系数法求出一次函数的解析式，全等三角形的性质和判定，解方程组，勾股定理，旋转的性质等知识点的应用，主要考查学生综合运用性质进行推理和计算的能力，题目比较好，但是有一定的难度．18.【答案】D【解析】解：由图象可知，甲乙两地的距离为450千米，故①说法正确；设轿车和货车的速度分别为V1千米/小时，V2千米/小时．根据题意得3V1+3V2=450.3V1−3V2=90.解得：V1=90，V2=60，故轿车和货车速度分别为90千米/小时，60千米/小时；故②③说法正确；轿车到达乙地的时间为450÷90=5(小时)，此时两车间的距离为(90+60)×(5−3)=300(千米)，故点C的实际意义是轿车出发5小时后到达乙地，此时两车间的距离为300千米．故④说法正确．所以说法正确的是①②③④．故选：D．由图象可知，甲乙两地的距离为450千米；设两车相遇时，设轿车和货车的速度分别为V1千米/小时，V2千米/小时，根据相遇时：轿车路程+货车路程=甲乙两地距离，轿车路程−货车路程=90，列方程组求解即可求出两车的速度；根据两车相遇后继续前行，轿车到达乙地时，两车之间的距离为y(千米)，即可得出点C的实际意义．本题考查了一次函数的运用．关键是通过图象，求出直线解析式，利用直线解析式求A点坐标，得出甲乙两地距离，再根据路程、速度、时间的关系解题．19.【答案】B【解析】【分析】本题考查轴对称的运用，有很强的综合性，难度较大．根据轴对称的性质及待定系数法可求得答案．【解答】解：作A 关于直线y =−x 对称点C ，易得C 的坐标为(−1,0)；连接BC ，设直线BC 的解析式为y =kx +b ， 则{−k +b =03k 2+b =−2，解得{k =−45b =−45, 可得直线BC 的解析式为y =−45x −45；由{y =−45x −45y =−x得BC 与直线y =−x 的交点坐标为(4,−4)； ∵|PA −PB|=|PC −PB|≤BC ，当C 、B 、P 共线时，|PA −PB|取得最大值BC ，故此时P(4,−4)．故选：B ．20.【答案】B【解析】本题为一次函数图象的应用题，属于中档题．根据图象求出甲乙的速度、函数表达式，逐项分析即可．解：①甲的速度为1203=40千米/小时，故正确；②t ≤1时，乙的速度为501=50千米/小时，t >1后，乙的速度为120−503−1=35千米/小时，故错误；③行驶1小时时，甲走了40千米，乙走了50千米，乙在甲前10千米处，故正确；④由①②③得：甲的函数表达式为：y =40t ，乙的函数表达为：0≤t ≤1时，y =50t ，t >1时，y =35t +15，t =0.5时，甲、乙两名运动员相距=50×12−40×12=5，t =2时，甲、乙两名运动员相距=(35×2+15)−2×40=5，同理可得，t =4时，甲、乙两名运动员相距为5，故错误．综上，正确的有①③，故选：B ．21.【答案】B【解析】解：由题意可知：x −2≥0，∴x ≥2，故选：B ．根据二次根式有意义的条件即可求出答案本题考查二次根式有意义的条件，解题的关键是正确理解有意义的条件，本题属于基础题型．22.【答案】B【解析】解：因为a<0，b≠0，所以√−a3b=−a√−ab，故选：B．根据二次根式的性质化简解答即可．此题考查二次根式的性质和化简，关键是根据二次根式的性质化简解答．23.【答案】D【解析】解：由题意得，2x−1≥0且x≠0，解得x≥12．故选：D．根据二次根式的被开方数非负且分母不等于0列式计算即可得解．本题考查了函数自变量的取值范围，一般从三个方面考虑：(1)当函数表达式是整式时，自变量可取全体实数；(2)当函数表达式是分式时，考虑分式的分母不能为0；(3)当函数表达式是二次根式时，被开方数非负．24.【答案】D【解析】解：由二次根式的非负性及被开方数的非负性可得：3x−5≥0∴x≥5 3∴1−3x<0∴√1−6x+9x2−(√3x−5)2=√(1−3x)2−(3x−5)=3x−1−3x+5=4故选：D．由二次根式的非负性及被开方数的非负性可得x的范围，从而可将根号化简掉，从而问题可解．本题考查了二次根式的性质与化简，明确被开方数的特点，会利用完全平方公式化简，是解题的关键．25.【答案】C【解析】【分析】本题考查的是轴对称−最短路线问题，熟知等腰三角形三线合一的性质是解答此题的关键．连接AD，由于△ABC是等腰三角形，点D是底边BC的中点，故AD⊥BC，再根据三角形的面积公式求出AD的长，再根据EF是线段AC的垂直平分线可知，点C关于直线EF的对称点为点A，故AD的长为CM+MD 的最小值，由此即可得出结论．【解答】解：连接AD，∵△ABC是等腰三角形，点D是底边BC的中点，∴AD⊥BC，∴S△ABC=12BC⋅AD=12×4×AD=16，解得AD=8，∵EF是线段AC的垂直平分线，∴点C关于直线EF的对称点为点A，∴AD的长为CM+MD的最小值，∴△CDM的周长最短=(CM+MD)min+CD=AD+12BC=8+12×4=8+2=10．故选：C．26.【答案】A【解析】解：由题意可知，∠1+∠2=∠3+∠2=60°，∴∠1=∠3，又∵OB=O′B，AB=BC，∴△BO′A≌△BOC，又∵∠OBO′=60°，∴△BO′A可以由△BOC绕点B逆时针旋转60°得到，故结论①正确；如图①，连接OO′，∵OB=O′B，且∠OBO′=60°，∴△OBO′是等边三角形，∴OO′=OB=4．故结论②正确；∵△BO′A≌△BOC，∴O′A=5．在△AOO′中，三边长为3，4，5，这是一组勾股数，∴△AOO′是直角三角形，∠AOO′=90°，∴∠AOB=∠AOO′+∠BOO′=90°+60°=150°，故结论③正确；S四边形AOBO′=S△AOO′+S△OBO′=12×3×4+√34×42=6+4√3，故结论④错误；如图②所示，将△AOB绕点A逆时针旋转60°，使得AB与AC重合，点O旋转至O″点．易知△AOO″是边长为3的等边三角形，△COO″是边长为3、4、5的直角三角形，则S△AOC+S△AOB=S四边形AOCO″=S△COO″+S△AOO″=12×3×4+√34×32=6+94√3，故结论⑤正确．综上所述，正确的结论为：①②③⑤．证明△BO′A≌△BOC，又∠OBO′=60°，所以△BO′A可以由△BOC绕点B逆时针旋转60°得到，故结论①正确；由△OBO′是等边三角形，可知结论②正确；在△AOO′中，三边长为3，4，5，这是一组勾股数，故△AOO′是直角三角形；进而求得∠AOB=150°，故结论③正确；S四边形AOBO′=S△AOO′+S△OBO′=6+4√3，故结论④错误；如图②，将△AOB绕点A逆时针旋转60°，使得AB与AC重合，点O旋转至O″点．利用旋转变换构造等边三角形与直角三角形，将S△AOC+S△AOB转化为S△COO″+S△AOO″，计算可得结论⑤正确．本题考查了旋转变换中等边三角形，直角三角形的性质．利用勾股定理的逆定理，判定勾股数3、4、5所构成的三角形是直角三角形，这是本题的要点．在判定结论⑤时，将△AOB向不同方向旋转，体现了结论①−结论④解题思路的拓展应用．27.【答案】B【解析】解：设两直角边分别为a，b，斜边为c，∵直角三角形斜边上的中线等于斜边的一半，∴斜边c=2×2=4，∵直角三角形的周长是4+√26，∴a+b+c=4+√26，∴{a+b+c=4+√26a2+b2=42∴{a+b=√26a2+b2=16∴ab=12[(a+b)2−(a2+b2)]=12×(26−16)=5，故s三角形=12ab=52．故选：B．根据直角三角形的性质：在直角三角形中，斜边上的中线等于斜边的一半，可求得斜边的长，再根据直角三角形的周长和勾股定理，可求得两直角边的长或长的乘积，由此可求出这个三角形的面积．此题考查了二次根式的化简求值，在解题过程中，应了解直角三角形的一些特殊性质，在进行求解的时候使问题变得简单．28.【答案】B【解析】解：过点E作EG⊥AB于点G，如图：∵CD⊥AB于D，∴EG//CD，∴∠GEB=∠EFC，∵在Rt△ABC中，∠ACB=90°，又∵BE平分∠ABC，EG⊥AB，∴EG=EC．在Rt△ABC中，∠ACB=90°，AC=3，BC=4，∴AB=5．在Rt△EBC和Rt△EBG中，{EB=EBEC=EG，∴Rt△EBC≌Rt△EBG(HL)，∠CEB=∠GEB，BG=BC=4，∴∠CEB=∠EFC，AG=AB−BG=5−4=1，∴CF=CE．设CF=EG=EC=x，则AE=3−x，在Rt△AEG中，由勾股定理得：(3−x)2=x2+12，解得x=43∴CF的长是43．故选：B．过点E作EG⊥AB于点G，由EG⊥AB，CD⊥AB，可得EG//CD，由平行线的性质可得∠GEB=∠EFC；在Rt△ABC中，由勾股定理求得AB的值；由HL判定Rt△EBC≌Rt△EBG，由全等三角形的性质可得∠CEB=∠EFC及AG的值，进而可判定CF=CE.设CF=EG=EC=x，则AE=3−x，在Rt△AEG中，由勾股定理得关于x的方程，解得x的值即为CF的长．本题主要考查了勾股定理、角平分线的性质定理及等腰三角形的判定等知识点，数形结合并熟练掌握相关性质及定理是解题的关键．29.【答案】A【解析】解：∵∠C=90°，AC=√3，BC=1，∴AB=√AC2+BC2=2，∴∠BAC=30°，∵△ADB沿直线BD翻折后，点A落在点E处，∴BE=BA=2，∠BED=∠BAD=30°，DA=DE，∵AD⊥ED，∴BC//DE，∴∠CBF=∠BED=30°，在Rt△BCF中，CF=3=√33，BF=2CF=2√33，∴EF=2−2√33，在Rt△DEF中，FD=12EF=1−√33，ED=√3FD=√3−1，∴S△ABE=S△ABD+S△BED+S△ADE =2S△ABD+S△ADE=2×12BC⋅AD+12AD⋅ED=2×12×1×(√3−1)+12×(√3−1)(√3−1) =1．故选A ．先根据勾股定理计算出AB =2，根据含30度的直角三角形三边的关系得到∠BAC =30°，在根据折叠的性质得BE =BA =2，∠BED =∠BAD =30°，DA =DE ，由于AD ⊥ED 得BC//DE ，所以∠CBF =∠BED =30°，在Rt △BCF 中可计算出CF =√33，BF =2CF =2√33，则EF =2−2√33，在Rt △DEF 中计算出FD =1−√33，ED =√3−1，然后利用S △ABE =S △ABD +S △BED +S △ADE =2S △ABD +S △ADE 计算即可．本题考查了折叠问题：折叠前后两图形全等，即对应线段相等；对应角相等．也考查了勾股定理和含30度的直角三角形三边的关系．30.【答案】B【解析】【分析】本题考查了轴对称−最短路线问题，勾股定理，等腰三角形的判定和性质，角平分线的定义，正确的作出辅助线是解题的关键．根据勾股定理得到BE =3，故①正确；求得AE =CE =5，根据平行线的性质和等腰三角形的性质即可得到PE 平分∠AEC ，故②正确；如图1，作C 关于直线AD 的对称点G ，连接GE 交AD 于P ，根据勾股定理得到GE =√CG 2+CE 2=√82+52=√89，求得△PEC 周长的最小值为√89+5，故③错误；如图2，过E 作EH ⊥AD 于H ，根据勾股定理得到PE =√PH 2+HE 2=√(76)2+42=256，求得∠PAE =∠PEA ，根据平行线的性质得到∠PAE =∠AEB ，求得∠PEA =∠AEB ，于是得到AE 平分∠BEP ，故④正确．【解答】解：∵AB =4，BC =8，∴AE =EC =BC −BE =8−BE ，∵AB 2+BE 2=AE 2，∴42+BE 2=(8−BE)2，∴BE =3，故①正确；∴AE =CE =5，∵AP =5，∴AP =AE ，∴∠APE =∠AEP ，∵AP//CE ，∴∠APE =∠PEC ，∴∠AEP =∠PEC ，∴PE 平分∠AEC ，故②正确；如图1，作C 关于直线AD 的对称点G ，连接GE 交AD 于P ，则此时，△PEC 周长最小，且△PEC 周长的最小值=GE +CE ；∴CE =5，CG =2CD =8，∴GE =√CG 2+CE 2=√82+52=√89，∴△PEC 周长的最小值为√89+5，故③错误；如图2，过E 作EH ⊥AD 于H ，则AH =BE =3，EH =AB =4，∵AP =256， ∴PH =76，∴PE =√PH 2+HE 2=√(76)2+42=256，∴AP =PE ，∴∠PAE =∠PEA ，∵AP//BC ，∴∠PAE =∠AEB ，∴∠PEA =∠AEB ，∴AE 平分∠BEP ，故④正确；故选：B ．31.【答案】C【解析】解：A 、结果不是整式的积的形式，故本选项不符合题意；B 、根据平方差公式可知a 2−b 2=(a −b)(a +b)，故本选项不符合题意；C 、从左到右的变形，是分解因式，故本选项符合题意；D 、从左到右的变形中，是整式的乘法，故本选项不符合题意．故选：C ．因式分解是把一个多项式化为几个整式积的形式，根据定义进行选择．本题主要考查了分解因式的定义，正确理解定义是关键．32.【答案】C。
2020-2021学年沈阳市东北育才实验学校高三英语上学期期末考试试题及参考答案
2020-2021学年沈阳市东北育才实验学校高三英语上学期期末考试试题及参考答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项ACome and enjoy Vivaldi's TheFour Seasonsperformed by live musicians!Tickets△Zone A Sating (Excellent Visibility, $75)△Zone B Seating (Great Visibility, $60)△Zone C Seating (Good Visibility, $45)△Zone D Seating (Restricted Visibility, 30)Zone A and Zone B audiences will get the chance to take pictures with the performers on the stage after the show.Highlights* A beautiful venue bathed in candlelight.*Classical music performance by the Angel Strings quartet*A safe and socially-distanced event, ensuring you are comfortable and at ease.General Info*Dates and times: Various dates, at 6:30 pm and 8:30 pm (select during purchase).*How long: 65 minutes. Doors open 45 minutes before the start time. We recommend you arrive at least 30 minutes before the start of the event, as late entry is not permitted.*Where: Events on Oxlade*Age requirement: Must be 8 years old or older to attend. Anyone under the age of 16 must be accompanied by an adult.*Please note: The 6:30 pm seating will take place during daylight hours outdoors, and the space will not be that dark. In the case of rain, the event will be moved to the indoor area of the venue.DescriptionWhether you're looking for a beautifully unique classical music performance or a romantic candlelit experience, this performance is for you. You don't need to know all things about Vivaldi to enjoy the evening;simply sit back and admire the wonderful atmosphere and the pieces you'll hear.Join our musicians for an evening under the stars, and prepare to be taken into the clouds with Vivaldi' s most treasured masterpieces!1.What can someone with a $45 ticket do?A.Perform on the stage.B.Enjoy good visibility.C.Select a seat in Zone B.D.Take photos with the musicians.2.What should potential audiences keep in mind?A.Arrive at the venue on time.B.Learn about Vivaldi in advance.C.The performance lasts 45 minutes.D.The event will be canceled if it rains.3.What do we know about the 8:30 p.m. performance?A.It welcomes children under the age of 8.B.Its performers differ on different dates.C.Its stage will be decorated with candles.D.It will be shown in the indoor area of the venue.BSome people take their holiday decoration very seriously. And some take it to the next level. The Griffith family in Kenova, West Virginia, is in this camp. They put on a display that shows they’re just filled with Halloween spirit.Each year, this family displays 3,000 pumpkins (南瓜) in front of their home for the Halloween season. Yes, you readthatright. Ric Griffith puts out one jack-o’ -lantern (南瓜灯) for every person who lives in Kenova.Of course he doesn’t do it all on his own. He has a lot of help from his family, and also from members of the community who are super-proud of what has become quite the tourist attraction over the years. More than 30,000 people stop by to see the amazing display, which includes jack△o’△lanterns cut to look like the faces of famous people, animals, cartoon characters, and other creative designs. It’s certainly a must-see as part of the area’s Ceredo-Kenova Autumnfest.To fit in all 3,000 pumpkins, Griffith and his helpers spread them across the home’s garden and front porch (门廊), as well as on the roof!Griffith began the tradition back in 1978 with just fivepumpkins and, many years later, it’s much bigger and better. People can’t help but come to the area, walking along the sidewalk outside the house to get that perfect Halloween experience.“Locals take great pride in it, and then there are people from around the country who plan fall trips and include it in their trips so they can see it,” said Tyson Compton, president of the Cabell△Huntington Convention and Visitors Bureau. “It’s really something.”“It’s become a tradition for many people in our area, and it feels good to keep that going,” Griffith said.4. What does the underlined word “that” in Paragraph 2 refer to?A. The Griffiths selling 3,000 pumpkins a day.B. Ric Griffith giving 3,000 jack-o’△lanterns to tourists.C. Ric Griffith teaching 3,000 people how to display jack-o’△lanterns.D. The Griffiths decorating their house with 3,000 pumpkins.5. What can we learn from Paragraph 3?A. Ric Griffith’s idea has received support from his community.B. There are only two kinds of jack-o’△lanterns.C. Ric Griffith dislikes asking for help from others.D. There are 30,000 people in Kenova.6. What do we know about the tradition?A. It began with 1,978 pumpkins.B. It has lasted more than 40 years.C. It includes five pumpkin competitions.D. It encourages people to do more exercise.7. What’s Tyson Compton’s attitude towards the tradition?A. Worried.B. Uncaring.C. Favorable.D. Uncertain.CFor decades, an organization, called Ulum Dalska, based in a small Swedish town called Alvdalen, hasbeen working hard to help save a language called EIfdalian. Elfdalian sounds nothing like the country's national language, Swedish, which press secretary Bjorm Rehnstrom said affected the language about 100 years ago. At that point, Elfdalian declined. Ulla Schitt, also a Ulum Dalska member, experienced the change while growing up in Alvdalen.“My parents spoke Efdalian with each other, and with my grandma and my aunts and uncles and everyone around,”Schit said. “But when they turned to me, they spoke Swedish.” Schitt said her parents spoke Swedish with her because that's what was spoken in schools.But people are getting creative in the fight to change that trend. Musicians are creating new songs with Elfdalian. Several children's books were also translated into EIfdalian, including Le Petit Prince by Antoine de Saint-Exupery. Additionally, Bjorm Rehnstrom helps run a popular Facebook group that offers courses in the Elfdalian language, where he offers lessons to the group's 1,800 global members from America, Australia, South America, Indonesia, Haiti and Cape Verde.The local government supports the teaching and preservation of Elfdalian. Bjom Rehnstrom said they eagerly paid for a sign that reads: “Welcome to Alvdalen” in Elfdalian. But the national government of Sweden is a different story. They currently consider Eidalian a dialect of Swedish, not its own language.Schitt said every time a language dies it is a sad moment. To her, losing Elfdalian would be an especially tragic (悲剧的) loss. “It's a part of our identity. It's part of our culture,” she said. “And if part of your identity and culture dies, a part of yourself dies.” Getting Elfdalian recognized as a language by the Swedish government, she added, is key to making sure that death doesn't come.8. Why was Ulum Dalska founded?A. To teach Swedish.B. To save Elfdalian.C. To improve Alvdalen.D. To help schools.9. Why Schitt's parents spoke Swedish with her?A. They could only speak Swedish fluently.B. Schitt longed to speak Swedish at home.C. Swedish was the language of schools.D. It was required by her school teachers,10. What can we infer from paragraph 4?A. Many people are trying to help to save Elfdalian.B. Songs in Elfdalian are becoming more popular.C. Le Petit Prince was translated into various languages.D. Courses in Eldalian are provided to the world freely.11. What does Schitt think of preserving Elfdalian?A. Satisfactory.B. Vital.C. Dangerous.D. Meaningless.DThe man who invented the World Wide Web a few decades ago is calling for major changes to make it better for humans. In an open letter published on Tuesday, Berners-Lee said that the web was used by half the world's population.Berners-Lee said the web had clearly created great opportunities for humans to progress and had made life easier for millions of people. Actually, it also has offered opportunities to groups traditionally not heard a new voice in society. However, he added that the web had also provided new ways for cheats to commit crimes (犯罪).“Against the background of news stories about how the web is misused, it's understandable that many people feel afraid and unsure if the web is really a force for good,” he wrote.Berners-Lee created a group called the World Wide Web Foundation. He islooking for help from governments, companies and people to become more involved in shaping the web to do more good for humans. His actual plan is called the “Contract (合同) for the Web”.Under this contract, governments are called on to take steps to makesure all people can connect to the Internet and that personal privacy is respected. Businesses are asked to keep the Internet prices low so more people can use the web. In addition, companies should respect privacy and develop technologies that aim to put people first.The plan also calls on people to create materials for the web and work with others to make sure that is rich, quality information for everyone. Besides, people should seek to “build strong communities that respect personal speech and human equality.” “The path to make the Internet better is the responsibility of everyone who uses it,” Bermers-Lee added, “Making big changes will not be easy, but will be very well worth it in the end.”12. What does Berners-Lee think of the World Wide Web?A. It is his greatest regret.B. It stops the progress of humans.C. It needs improving.D. It does more harm than good.13. What's wrong with the web according to Berners-Lee?A. It is misused for bad purposes.B. It is misunderstood by all people.C. It blocks out a new voice in society.D. It is expensive for half the world’s population.14. What are governments called on to do under the “Contract for the Web”?A. Put technology first.B. Create materials for the web.C. Popularize the Internet.D. Make the Internet free of charge.15. What should people do with the Internet in Berners-Lee's opinion?A. Be responsible for it.B. Absolutely reject it.C. Completely rely on it.D. Be unconcerned about it.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。
2020-2021学年东北育才学校高三英语上学期期末试卷及答案
2020-2021学年东北育才学校高三英语上学期期末试卷及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项ASheffieldLincoln College of EnglishClasses for foreign students at all levels.3 months, 6 months, 9 months and one year course.Open all year.Small class (at most 12 students).Library, language laboratory and listening center.Accommodation (住宿)with selected families.25 minutes from London.Course fees for English for one year are￡1,380 with reduction for shorter periods of study.1.This passage is probably taken from _______.A.an advertisementB.a noticeC.a posterD.a piece of news2.Who will be accepted by this college?A.Both foreign and native students.B.Only foreign beginners and the advanced.C.Foreign students from beginners to the advanced.D.Only foreign students advanced.3.While you stay there, who will take care of you?A.Your parents.B.Your classmates.C.The school where you study.D.The family you have chosen.BPigeons inLondonhave a bad reputation. Some people call them flying rats. And many blame them for causing pollution with their droppings. But now the birds are being used to fight another kind of pollution in this city of 8.5 million.“The problem for air pollution is that it’s been largely ignored as an issue for a long time,” says Andrea Lee, who works for the London-based environmental organization Client Earth. “People don’t realize how bad it is, and how it actually affects their health.”London’s poor air quality is linked to nearly 10,000 early deaths a year. Lee says, citing(引用)a report released by the city manager last year. If people were better informed about the pollution they’ re breathing, she says, they could pressure the government to do something about it.Nearby, on a windy hill inLondon’s Regent’s Park, an experiment is underway that could help—the first week of flights by the Pigeon Air Patrol. It all began when Pierre Duquesnoy, the director for DigitasLBi, a marketing firm, won a London Design Festival contest last year to show how a world problem could be solved using Twitter. Duquesnoy, fromFrance, chose the problem of air pollution.“Basically, I realized how important the problem was,” he says. “But also I realized that most of the people around me didn’t know anything about it.” Duquesnoy says he wants to better measure pollution, while at the same time making the results accessible to the public through Twitter.“So”, he wondered, “how could we go across the city quickly collecting as much data as possible?” Drones were his first thought. But it’s illegal to fly them overLondon. “But pigeons can fly aboveLondon, right?” he says. “They live—actually, they are Londoners as well. So, yeah, I thought about using pigeons equipped with mobile apps. And we can use not just street pigeons, but racing pigeons, because they fly pretty quickly and pretty low.”So it might be time for Londoners to have more respect for their pigeons. The birds may just be helping to improve the quality of the city’s air.4. What can we infer aboutLondon’s air quality from Paragraph 2?A. Londoners are very satisfied with it.B. The government is trying to improve it.C Londoners should pay more attention to it.D. The government has done a lot to improve it.5. Duquesnoy attended the London Design Festival to _________.A. entertain Londoners.B. solve a world problem.C. design a product for sale.D. protect animals like pigeons.6. Why did Duquesnoy give up using drones to fly acrossLondon?A. Because they are too expensive.B. Because they fly too quickly.C. Because they are forbidden.D. Because they fly too high.7. Which can be the best title for the text?A. Clean air inLondon.B. London’s dirty secret.C. London’s new pollution fighter.D. Causes of air pollution inLondon.CSurfing the Internet for fun will make you a better employee, according to an Australian study.The University of Melbourne study shows that people who use the Internet for their own reasons at work are about 9 percent more productive than those who do not. Study author Brent Coker said, “Surfing the Internet at times helps increase an employee's attention.”“People need to relax for a bit to get back their attention,” Coker said on the university's website. “Having a short break, such as a quick surfing of the Internet, helps the mind to rest itself, leading to a higher total Internet attention for a day's work, and as a result, increases productivity (生产效率),” he said.According to the study of 300 workers, 70 percent of people who use the Internet at work surf the Internet for their own reasons during office hours. Among the most popular surfing activities are searching for information about products, reading online news, playing online games and watching videos. “Firms spend a lot of money on software toblocktheir employees from watching videos, using social networking sites or shopping online,” said Coker. “That's not always a good idea.”However, Coker said the study looked at people who surfed the Internet in moderation (适度), or were on the Internet for less than 20 percent of their total time in the office. “Those who spend too much time surfing the Internet will have a lower productivity than those without.” he said.8. What does the University of Melbourne study mainlyshow?A. People who surf the Internet are good employees.B. Not everyone surfs the Internet for fun during office hours.C. The Internet is becoming more and more important in people's life.D. Surfing the Internet for fun at times during office hours increases productivity.9. Which of the following is NOT mentioned in the passage as one of the most popular surfing activities?A. Watching videos.B. Reading online news.C. Reading online novels.D. Playing online games.10. The underlined word “block” in Paragraph 4 means “________”.A. stopB. organizeC. protectD. separate11. What can we infer from the last paragraph?A. Those who never surf the Internet have the lowest productivity.B. Spending too much time surfing the Internet reduces productivity.C. Most people don't surf the Internet in moderation during office hours.D. People should spend as little time as possible surfing the Internet.DOne day, when I was working as a psychologist（心理学家）in England, an adolescent boy showed up in my office. It was David. He kept walking up and down restlessly, his face pale, and his hands shaking slightly. His head teacher had referred him to me.“This boy has lost his family,” he wrote. “He is understandably very sad and refuses to talk to others, and I’m very worried about him. Can you help?”I looked at David and showed him to a chair. How could I help him? There are problems psychology doesn’t have the answer to, and which no words can describe. Sometimes the best thing one can do is to listen openly and sympathetically（同情）The first two times we met, David didn’t say a word. He sat there, only looking up to look at the children’s drawings on the wall behind me. I suggested we play a game of chess. He nodded. After that he played chess with me every Wednesday afternoon---in complete silence and without looking at me. It’s not easy to cheat in chess, but I admit I made sure David won once or twice.Usually, he arrived earlier than agreed, took the chess board and pieces from the shelf and began setting them up before I even got a chance to sit down. It seemed as if he enjoyed my company（陪伴）. But why did he never look at me?“Perhaps he simply needs someone to share his pain with,” I thought. “Perhaps he senses that I respect his suffering.” Some months later, when we were playing chess, he looked up at me suddenly.“It’s your tum,” he said.After that day, David started talking. He got friends in school and joined a bicycle club. He wrote to me a few times, about his biking with some friends, and about his plan to get into university. Now he had really started to live his own life.Maybe I gave David something. But I also learned that one…without any words---can reach out to another person. All it takes is a hug, a shoulder to cry on, a friendly touch, and an ear that listens.12. When he first met the author, David .A. felt a little excitedB. looked a little nervousC. walked energeticallyD. showed up with his teacher13. David enjoyed being with the author because he .A. wanted to ask the author for adviceB. liked the children’s drawings in the officeC. beat the author many times in the chess gameD. needed to share sorrow with the author14. What can be inferred about David?A. He liked biking before he lost his family.B. He recovered after months of treatment.C. He went into university soon after starting to talk.D. He got friends in school before he met the author.15. What made David change?A. The author’s silent communication with him.B. His teacher’s help.C. The author’s friendship.D. His exchange of letters with the author.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。
2020-2021学年东北育才双语学校高三英语期末考试试题及答案
2020-2021学年东北育才双语学校高三英语期末考试试题及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项ABest Places to Visit in JulyNorway's FjordsMost travelers prefer to visit Norway's famous fjords (峡湾) in July because Norway has about 23 hours of daylight, giving travelers lots of time to take in the spectacular views of blue water, glaciers and mountains. July is also whenNorway's weather is at its warmest, about18℃, so travelers might include a light sweater in their luggage.Bastille Day inParisJuly 14 is a national day celebrating independence to the French. July 14, 1789, is the day the French stormed the Bastille, aParisprison, and officially began the French Revolution, overthrowing a royal government that often threw people in prison there for no reason at all. While the day is marked all overFrance, the biggest celebration takes place inParis.Masai Mara National ReserveThe thrill of seeing millions of animals wander the plains inKenyais not easily forgotten. One of the most popular months to visit the Masai Mara is in July when the famous wildlife migration reaches the Masai Mara and zebras are at their highest number. The best times to view the animals inKenya's most popular game park are dawn and dusk.Running of the Bulls inPamplonaTravelers who pride themselves on being fast runners may want to head toPamplonain July for the San Femin Festival. A key part of this annual festival is the running of the bulls. Six bulls are released onto a narrow street fora half-mile run, with hundreds of runners seeing if they can run faster than the animals.1. What can visitors do inNorway's in July?A. Enjoy the impressive scenery.B. Swim and fish in the fjords.C. See daylight around the clock.D. Buy heavy sweaters to keep warm.2. Which of the following is of historical significance?A. San Fermin Festival.B. Bastille Day.C. Masai Mara National Reserve.D.Norway's Fjords.3. Where will visitors interested in wild animals go?A. Norway.B. Paris.C. Masai Mara.D.Pamplona.BIn ancient times, Chinese used plant leaves or bird feathers as a fan during the summer time. This was the earliest form of the fan. The first real fan was made back in the era of Yao and Shun period thousands of years ago. Since then,Chinese-made fans have become a vital part of Chinese art and culture. At the beginning, the fan functioned as a tool to generate a current of air in the hot weather. Now electric fans such as ceiling fans and other technological breakthroughs have taken the place.Long ago, fans caught the attention of ancient Chinese artists by chance. Thereafter, a unique fan art gradually took shape in the history of Chinese culture. Fan art usually includes Chinese calligraphy, paintings, or poems on the sectors（扇区）. Special skills are needed to write or paint on them.Due to its history and partly because of its unique shape, Chinese would soon develop the tradition of using fans as ornaments（装饰品）. Fans are made in different sizes and different color1 s to meet the needs of each request. Other Chinese ornaments, such as the Chinese knot, the green jade, and the Spring Festival picture, are often combined in each design.The value of fans depends mainly on the materials used and the level of craftsmanship that is involved during the process. Feather, paper, jade, bamboo and silk have all been used as ideal materials to make fans. Ancient Chinese even made iron fans to serve as deadly weapons（武器）in Chinese martial arts. Fans made by famous craftsmen are often characterized by pretty designs and detailed workmanship, and thus become favorites of collectors. Fans with masterpiece fine art like calligraphy or paintings are even more valuable.4.What is the first paragraph mainly about?A. The origin of fans.B. The materials of fans.C. The popularity of fans.D. The production of fans.5. Why do Chinese use fans as ornaments?A. They are made of valuable materials.B. They reflect the beauty of Chinese culture.C. They convey literature works on the sectors.D. They are often combined with other ornaments.6. Which of the following makes a fan favored by most collectors?A. Its advanced function.B. Its complex character.C. Its artistic handicraft.D. Its various applications.7. What can we infer about the fan from the text?A. Chinese send fans to their friends as gifts.B. Chinese ornaments can meet different requests.C. Traditional fans have lost their functional value.D. The fan plays different roles with the change of time.CEvery day, millions of shoppers hit the stores in full force, searching wildly for the perfect gift.Aside from purchasing holiday gifts, most people regularly buy presents for other occasions throughout the year, including weddings, birthdays, anniversaries, and graduations. This frequent experience of gift-giving cancause uncertain feelings in gift-givers. Many enjoy the opportunity to buy presents because gift-giving offers a powerful means to build stronger bonds, while many worry that their purchases will disappoint rather than delight the intended recipients (接受者).Anthropologists describe gift-giving as a positive social process, serving various political, religious, and psychological functions. Economists, however, offer a less favorable view. According to Waldfogel, gift-giving represents an objective wasteof resources. People buy gifts that recipients would not choose to buy on their own, or at least not spend as much money to purchase (a phenomenon referred to as‘‘the deadweight loss of Christmas”).What is surprising is that gift-givers have much experience acting as both gift-givers and gift-recipients, but nevertheless tend to overspend each time they set out to purchase a meaningful gift. In the present research, we propose a unique psychological explanation for this overspending problem — gift-givers link how much they spend with how much recipients will appreciate the gift. Though it seems natural to gift-givers, such an assumption may be unfounded. Indeed, we propose that gift-recipients will be less likely to base their feelings of appreciation on the value of a gift than givers assume.Why do gift-givers assume that gift price is closely linked to gift-recipients’ feelings of appreciation? Perhaps givers believe that more expensive gifts communicate a stronger sense ofthoughtfulness and consideration. According to Camerer and others, gift-giving represents a symbolic ritual (习俗), by which gift-givers attempt to signal their positive attitudes towards the recipient and their willingness to invest resources in a futurerelationship.In this sense, gift-givers may be motivated to spend more money on a gift in order to send a “stronger signal”. As for gift-recipients, they may not interpret smaller and larger gifts as representing smaller and larger signals of thoughtfulness and consideration.The idea of gift-givers and gift-recipients being unable to account for the other party’s viewpoint seems confusing because people slip in and out of these roles every day. Yet, despite the experience as both givers and receivers, people often struggle to apply information gained from one role in another. In theoretical terms, people fail to use information about their own preferences and experiences to produce more efficient outcomes in their exchange relations. In practical terms, people spend hundreds of dollars each year on gifts, but somehow never learn to estimate their gift expense according to personal insight.8. The author uses “the deadweight loss of Christmas” in Paragraph 2 to express ________.A. gift-givers don’t spend much money during holidaysB. gift-givers don’t ask recipients what gifts they preferC. gift-givers buy improper and expensive giftsD. gift-givers have difficulty in choosing gifts9. According to the passage, people buy gifts to ________.A. receive gifts in returnB. enjoy the feeling of shoppingC. help recipients to save moneyD. better relationships with recipients10. What can we learn from the passage?A. People’s high living standards require expensive gifts.B. Gift-givers buy gifts based on their experiences as recipients.C. Anthropologists think gift-giving meets different human needs.D. Recipients judge the depth of friendship according to the gift price.11. Why did the author write this article?A. To criticize people’s gift-buying habits.B. To analyze people’s gift-giving behaviors.C. To offer advice on how to improve relationships.D. To remind people not to overlook others’ preferences.DJerry Lawson had a love of science and invention from a very young age. And, with the support of his family and teachers, he took that love and helped change the world for billions of people, when he invented the modem video game cartridge.Both of Jerry's parents supported his love of science and invention. His father, a longshoreman, was a science fan and encouraged Jerry to always experiment with things. Jerry's first-grade teacher helped encourage him on his path to be someone influential similar to George Washington Carver, a great AfricanAmerican inventor. His first love in school was chemistry but he ended up liking electronics（电子学）even more.He earned an amateur ham radio license at age 13 and built his own radio station in his room, with an antenna hanging out of his window! Jerry earned money from fixing television sets, visiting people's homes for inhouse repair, and also working at local electronics stores. Jerry also made walkie-talkies and sold them to other kids. He spent many Saturdays at an electronics store that had all of the parts he needed for his inventions. He would use his small allowance and money he earned to buy parts to help fuel his inventions.When he was a young adult, Jerry joined Fairchild Semiconductor as an engineer. During this time, he created his own video arcade game（街机游戏），Demolition Derby, in his garage.A few years later, Jerry was asked to work on a secret project. Not even his boss was allowed to know what he was doing! What it turned out to be was that he was designing the Fairchild Channel F video gameconsole（游戏控制器）and leading the team that invented the video game cartridge. This was the first of its kind and enabled kids around the world to affordably play video games at home.Just like with automobiles，many advances have occurred since the inventionof video games. Video games are now one of the biggest forms of entertainment in the world. But all of this would not have been possible without the vision, passion, and skill of Jerry Lawson and his learn.12. How did Jerry earn money when he was a teenager?A. By running his radio station.B. By selling television sets.C. By repairing things for others.D. By making electronic parts.13. Before Jerry's secret project, playing video games at home was_____.A. expensiveB. harmfulC. commonD. tiring14. What does the author mainly tell us in the last paragraph?A. Jerry Lawson and his team can be more skillful.B. Jerry Lawson is important to the game industry.C.Many advances have taken place in the automobile industry.D. Video games are now the most popular form of entertainment.15. What can be the best title for the text?A. Video Gaming-An Important IndustryB. Game Console-Key to Home Video GamesC. Jerry Lawson-Father of Modern GamingD. Support and Encouragement-Necessary for Success第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。
2020-2021学年东北育才双语学校高三语文期末试题及答案
2020-2021学年东北育才双语学校高三语文期末试题及答案一、现代文阅读（36分）(一)现代文阅读I(9分)阅读下面的文字，完成下面小题。
材料一：国家统计局数据显示，2018年我国粮食产量突破13000亿斤。
我国粮食产量已经连续多年稳定在12000亿斤以上。
国内粮食市场的基本稳定是对世界粮食安全的重大贡献。
“我国人口众多、农业资源人均占有水平低，虽然近年来粮食连年丰收，仍然无法完全做到自给自足。
国际贸易是保障粮食安全的重要手段。
”中国粮食行业协会会长于旭波说。
我国耕地占全球近10%、淡水资源占6%，却要养活全球近20%的人口，资源与人口完全不对等。
随着我国经济的发展和城市化水平的不断提高，人们的消费需求不断升级，正由“吃得饱”向“吃得好”转变，部分粮食出现了较大供求缺口，需要通过国际贸易来适当调剂余缺。
增强保障粮食安全应该植根于国内粮食供应基础之上。
目前全球粮食贸易量每年在4亿吨左右，仅占我国年消费量的三分之二。
此外，当前我国粮食个别品种供求矛盾突出，大豆对外依赖程度超过80%，优质粮食供给成为“短板”。
我国粮食安全是有保障的，但从中长期看，无论中国还是全球，粮食安全都隐患不少，风险仍然存在，需要各国加强合作，扩大贸易流通，促进全球粮食资源合理流动，提升整体粮食安全水平。
（刘慧《我国筑牢粮食安全屏障》，选自《经济日报》2019年1月）材料二：“到2020年全国耕地保有量不少于18.65亿亩，永久基本农田保护面积不少于15.46亿亩，确保建成8亿亩，力争建成10亿亩高标准农田。
”1月24日国新办新闻发布会上，国土资源部部长姜大明在解读《关于加强耕地保护和改进占补平衡的意见》时说。
农业部副部长余欣荣说：“严格实施耕地的数量保护，既要‘少占’，也要‘补足’。
就是说要减少新增建设占用耕地，同时要拓展补充耕地渠道。
”对于加强保护耕地质量，余欣荣说：“耕地是生态系统的重要一环，在耕地后备资源开发利用的同时，要积极开展退化耕地的综合治理，污染耕地的治理修复，统筹推进耕地休养生息。