备战2021高考英语热点题型和提分秘籍 专题02 冠词(原卷版) Word版缺答案
(2021-2023)新高考英语真题分项汇编专题02代词介词介词短语(原卷版)

专题02 代词、介词、介词短语1. (2023年新高考I卷)There you will find them prepared differently—more dumpling and less soup, and the wrappers are pressed_______hand rather than rolled.2. (2023年新高考I卷)Nanxiang aside, the best Xiao long bao have a fine skin, allowing them to be lifted out of the steamer basket without tearing or spilling any of ________(they) contents.3.(2023年新高考II卷)And who do they speak English ________?4.(2023年浙江卷1月)Thanks to Beijing’s long history capital of China, almost every hutong has its stories, and some are even associated with historic events.1.(2022年新高考I卷)Giant pandas also serve ______ an umbrella species(物种), bringing protection to a host of plants and animals in the southwestern and northwestern parts of China. (用适当的词填空)2.(2022年北京卷)Helen was walking down the street late ________ the evening, her arms filled with grocery bags. (用适当的词填空)3.(2022年天津卷)I’m far________ and I’ll never get this report done by Friday.A. below surfaceB. beyond controlC. behind scheduleD. above average4.(2022年北京卷)Since people can’t always eat out or cook for ________ (they), they get takeout or order delivery.5.(2022年浙江卷6月)Lu Gandarias, who’s now thirteen, went blind suddenly ________ age seven.1.(2021年浙江卷1月)The study found that between 1985 and 2017, average rural BMI increased ________2.1 in women and men.(用适当的词填空)2.(2021年浙江卷6月)In 1844 they bought it ________ $1,200 and some land from Charles Dresser.(用适当的词填空)3.(2021年浙江卷6月)She was extremely pretty, and her house was a reflection of ________ (she), everything in good taste and in perfect order. (所给词的适当形式填空)4.(2021年北京卷)While riding his bike home ________ a cold night,he came across a sad-looking elderlywoman wandering the streets by herself.。
备战2021高考理数热点题型和提分秘籍 专题20 简单的三角恒等变换(解析版)

专题二十 简洁的三角恒等变换【高频考点解读】1.把握二倍角的正弦、余弦、正切公式.2.能运用两角和与差的正弦、余弦、正切公式以及二倍角的正弦、余弦和正切公式进行简洁的恒等变换(包括导出积化和差、和差化积、半角公式,但对这三组公式不要求记忆).【热点题型】题型一 已知三角函数值求值例1、已知角A 、B 、C 为△ABC 的三个内角,OM →=(sin B +cos B ,cos C ),ON →=(sin C ,sin B -cos B ),OM →·ON →=-15.(1)求tan2A 的值;(2)求2cos 2A2-3sin A -12sin A +π4的值.(2)∵tan A =-34,∴2cos 2A2-3sin A -12sin A +π4=cos A -3sin A cos A +sin A =1-3tan A1+tan A=1-3×-341+-34=13.【提分秘籍】对于条件求值问题,即由给出的某些角的三角函数值,求另外一些角的三角函数值,关键在于“变角”即使“目标角”变换成“已知角”.若角所在象限没有确定,则应分状况争辩,应留意公式的正用、逆用、变形运用,把握其结构特征,还要留意拆角、拼角等技巧的运用.【举一反三】已知α∈(π2,π),且sin α2+cos α2=62.(1)求cos α的值;(2)若sin(α-β)=-35,β∈(π2,π),求cos β的值.【热点题型】题型二 已知三角函数值求角例2、如图,在平面直角坐标系xOy 中,以Ox 轴为始边做两个锐角α、β,它们的终边分别与单位圆相交于A 、B 两点,已知A 、B 两点的横坐标分别为210,255.(1)求tan(α+β)的值; (2)求α+2β的值.又∵α、β为锐角, ∴0<α+2β<3π2,∴α+2β=3π4.【提分秘籍】(1)已知某些相关条件,求角的解题步骤: ①求出该角的范围;②结合该角的范围求出该角的三角函数值.(2)依据角的函数值求角时,选取的函数在这个范围内应是单调的. 【举一反三】已知向量a =(sin θ,-2)与b =(1,cos θ)相互垂直,其中θ∈(0,π2).(1)求sin θ和cos θ的值;(2)若sin(θ-φ)=1010,0<φ<π2,求φ的值.【热点题型】题型三 正、余弦定理的应用例3、在△ABC 中,内角A ,B ,C 的对边分别为a ,b ,c .已知cos A -2cos C cos B =2c -ab .(1)求sin Csin A的值;(2)若cos B =14,b =2,求△ABC 的面积S .【解析】 (1)由正弦定理,设a sin A =b sin B =csin C=k ,【提分秘籍】(1)利用正弦定理,实施角的正弦化为边时只能是用a 替换sin A ,用b 替换sin B ,用c 替换sin C . sin A ,sin B ,sin C 的次数要相等,各项要同时替换,反之,用角的正弦替换边时也要这样,不能只替换一部分;(2)以三角形为背景的题目,要留意三角形的内角和定理的使用.像本例中B +C =60°;(3)在求角的大小肯定要有两个条件才能完成:①角的范围;②角的某一三角函数值.在由三角函数值来推断角的大小时,肯定要留意角的范围及三角函数的单调性.【举一反三】在锐角△ABC 中,a 、b 、c 分别为A 、B 、C 所对的边,且3a =2c sin A . (1)确定角C 的大小;(2)若c =7,且△ABC 的面积为332,求a +b 的值.解:(1)由3a =2c sin A ,依据正弦定理,sin C =c sin A a =32,又0<C <π2,则C =π3.【热点题型】题型四 解三角形与实际问题例4、如图,A ,B 是海面上位于东西方向相距5(3+3)海里的两个观测点.现位于A 点北偏东45°,B 点北偏西60°的D 点有一艘轮船发出求救信号,位于B 点南偏西60°且与B 点相距203海里的C 点的救援船马上前往营救,其航行速度为30海里/时,该救援船到达D 点需要多长时间?又∠DBC =∠DBA +∠ABC =30°+(90°-60°)=60°,BC =203(海里),在△DBC 中,由余弦定理得 CD 2=BD 2+BC 2-2BD ·BC ·cos ∠DBC =300+1200-2×103×203×12=900,∴CD =30(海里),则需要的时间t =3030=1(小时).即该救援船到达D 点需要1小时.【提分秘籍】应用解三角形学问解决实际问题需要下列四步:(1)分析题意,精确 理解题意,分清已知与所求,尤其要理解题中的有关名词、术语,如坡度、仰角、俯角、视角、方位角等;(2)依据题意画出示意图,并将已知条件在图形中标出;(3)将所求问题归结到一个或几个三角形中,通过合理运用正、余弦定理等有关学问正确求解; (4)检验解出的结果是否具有实际意义,对结果进行取舍,得出正确答案. 【举一反三】如图所示,上午11时在某海岛上一观看点A 测得一轮船在海岛北偏东60°的C 处,12时20分测得船在海岛北偏西60°的B 处,12时40分轮船到达位于海岛正西方且距海岛5 km 的E 港口,假如轮船始终匀速直线前进,问船速为多少?在△ABE 中,由余弦定理,得BE 2=AB 2+AE 2-2AB ·AE ·cos30°=163+25-2×433×5×32=313,故BE =313. ∴船速v =BEt =31313=93 (km/h).故该船的速度为93 km/h. 【高考风向标】1.(2022·全国卷)直线l 1和l 2是圆x 2+y 2=2的两条切线.若l 1与l 2的交点为(1,3),则l 1与l 2的夹角的正切值等于________.2.(2022·全国卷)若函数f (x )=cos 2x +a sin x 在区间⎝⎛⎭⎫π6,π2是减函数,则a 的取值范围是________.3.(2022·福建卷)已知函数f (x )=cos x (sin x +cos x )-12.(1)若0<α<π2,且sin α=22,求f (α)的值;(2)求函数f (x )的最小正周期及单调递增区间.【解析】方法一:(1)由于0<α<π2,sin α=22,所以cos α=22.所以f (α)=22×⎝⎛⎭⎫22+22-12=12.4.(2022·四川卷)已知函数f (x )=sin ⎝⎛⎭⎫3x +π4. (1)求f (x )的单调递增区间;(2)若α是其次象限角,f ⎝⎛⎭⎫α3=45cos ⎝⎛⎭⎫α+π4cos 2α,求cos α-sin α的值. 【解析】(1)由于函数y =sin x 的单调递增区间为⎣⎡⎦⎤-π2+2k π,π2+2k π,k ∈Z , 由-π2+2k π≤3x +π4≤π2+2k π,k ∈Z ,得-π4+2k π3≤x ≤π12+2k π3,k ∈Z.所以,函数f (x )的单调递增区间为⎣⎡⎦⎤-π4+2k π3,π12+2k π3,k ∈Z.5.(2022·天津卷)已知函数f (x )=cos x ·sin ⎝⎛⎭⎫x +π3-3cos 2x +34,x ∈R. (1)求f (x )的最小正周期;(2)求f (x )在闭区间⎣⎡⎦⎤-π4,π4上的最大值和最小值.(2)由于f (x )在区间⎣⎡⎦⎤-π4,-π12上是减函数,在区间⎣⎡⎦⎤-π12,π4上是增函数,f ⎝⎛⎭⎫-π4=-14,f ⎝⎛⎭⎫-π12=-12,f ⎝⎛⎭⎫π4=14,所以函数f (x )在区间⎣⎡⎦⎤-π4,π4上的最大值为14,最小值为-12. 6.(2022·北京卷)如图1-2,在△ABC 中,∠B =π3,AB =8,点D 在BC 边上,且CD =2,cos ∠ADC =17.(1)求sin ∠BAD ; (2)求BD ,AC 的长.图1-27.(2022·福建卷)在△ABC 中,A =60°,AC =4,BC =23,则△ABC 的面积等于________.【答案】23 【解析】 由BC sin A =AC sin B ,得sin B =4sin 60°23=1,∴B =90°,C =180°-(A +B )=30°,则S △ABC =12·AC ·BC sin C =12×4×23sin 30°=23,即△ABC 的面积等于2 3.8.(2022·湖南卷)如图1-5所示,在平面四边形ABCD 中,AD =1,CD =2,AC =7.图1-5(1)求cos∠CAD的值;(2)若cos∠BAD =-714,sin∠CBA=216,求BC的长.9.(2022·四川卷)如图1-3所示,从气球A上测得正前方的河流的两岸B,C的俯角分别为67°,30°,此时气球的高度是46 m,则河流的宽度BC约等于________m.(用四舍五入法将结果精确到个位.参考数据:sin 67°≈0.92,cos 67°≈0.39,sin 37°≈0.60,cos 37°≈0.80,3≈1.73)10.(2021·四川卷)设sin 2α=-sin α,α∈⎝⎛⎭⎫π2,π,则tan 2α的值是________.11.(2021·重庆卷)在△ABC中,内角A,B,C的对边分别是a,b,c,且a2+b2+2ab=c2.(1)求C;(2)设cos Acos B=3 25,cos(α+A)cos(α+B)cos2α=25,求tan α的值.【解析】(1)由于a2+b2+2ab=c2,所以由余弦定理有cos C=a2+b2-c22ab=-2ab2ab=-22.故C=3π4.(2)由题意得(sin αsin A-cos αcos A)(sin αsin B-cos αcos B)cos2α=25,12.(2021·重庆卷)4cos 50°-tan 40°=( ) A. 2 B.2+32C. 3 D .2 2-1【随堂巩固】1.已知sin θ2=45,cos θ2=-35,则角θ所在的象限是( )A .第一象限B .其次象限C .第三象限D .第四象限解析:sin θ=2sin θ2cos θ2=2×45×(-35)<0.cos θ=cos 2θ2-sin 2θ2=925-1625=-725<0,∴θ是第三象限角.答案:C2.已知sin α=55,则cos4α的值是( ) A.425 B .-725C.1225D .-18253.若-2π<α<-3π2,则1-cos α-π2的值是( )A .sin α2B .cos α2C .-sin α2D .-cos α24.已知θ为其次象限角,sin(π-θ)=2425,则cos θ2的值为( )A.35B.45 C .±35D .±455.已知x ∈(π2,π),cos 2x =a ,则cos x =( )A.1-a2B .-1-a2C.1+a2D .-1+a2解析:依题意得cos 2x =1+cos 2x 2=1+a 2;又x ∈(π2,π),因此cos x =-1+a2. 答案:D6.若cos α=-45,α是第三象限角,则1+tanα21-tanα2=( )A .-12B.12 C .2D .-27.已知cos 2α=14,则sin 2α=________.解析:sin 2α=1-cos 2α2=38.答案:388.sin 2B1+cos 2B -sin 2B =-3,则tan 2B =________. 解析:sin 2B 1+cos 2B -sin 2B=2sin B cos B2cos 2B =tan B =-3.∴tan2B =2tan B 1-tan 2B =34.答案:349.设α是其次象限角,tan α=-43,且sin α2<cos α2,则cos α2=________.10.化简:2sin(π4-x )+6cos(π4-x )11.求3tan 10°+14cos 210°-2sin 10°的值.解:原式=3sin 10°+cos 10°cos 10°2cos 20°sin 10°=2sin 10°+30°2cos 20°sin 10°cos 10°=2sin 40°sin 20°cos 20°=2sin 40°12sin 40°=4.12.已知函数f (x )=3sin2x -2sin 2x . (1)求函数f (x )的最大值; (2)求函数f (x )的零点的集合.解:(1)由于f (x )=3sin 2x -(1-cos 2x ) =2sin(2x +π6)-1,所以,当2x +π6=2k π+π2,k ∈Z ,即x =k π+π6,k ∈Z时,函数f (x )取得最大值1.。
备战2021高考英语热点题型和提分秘籍 专题10 名词性从句(解析版) Word版含解析

专题十名词性从句【高频考点解读】考查名词性从句中引导词的选用,区分what,that,wh-ever,whether,if等连接代词和连接副词的语义功能和语法功能。
尤其是把名词性从句与定语从句放在一起进行综合考查,增加了试题的难度。
【热点题型】题型一考查主语从句及连接词的辨析例1、It is by no means clear the president can do to end the strike.A.how B.which C.that D.what【提分秘籍】that与what的区分1.引导名词性从句时,that没有意义,在从句中不作任何成分。
因此当从句意义完整,不缺任何成分时,往往用that,that引导主语从句、同位语从句、表语从句时不行省略。
2.what引导名词性从句时,意为“什么”(有时候可以不译出来)在从句中作主语、表语或宾语,从不行省略。
【举一反三】It suddenly occurred to him he had left his keys in the office.A.whether B.whereC.which D.that【热点题型】题型二考查宾语从句及连接词的辨析例2、We promise attends the party a chance to have a photo taken with the movie star.A.who B.whomC.whoever D.whomever 【提分秘籍】“疑问词”与“疑问词+ever”的区分“疑问词+ever”可以引导名词性从句,含有“无论……”之意,用法与“疑问词”一样,只是语气比疑问词本身的语气猛烈得多。
“疑问词+ever”与“no matter+疑问词”的区分①“疑问词+ever”引导名词性从句时,whoever=anyone who,whatever=anything that等。
如:Whoever(=Anyone who)comes is welcome.②“no matter+疑问词”只能用来引导状语从句。
2021届高考英语单项选择题分类汇总 冠词部分(word版含解析)

高中英语单项选择题分类汇总冠词部分总结:①三餐前一般不加冠词,但如果有形容词修饰,则加不定冠词,eg:have a light /good breakfast 吃简单/丰盛的早餐②act as 担当,后面接表示官衔、头衔的名词时,一般不用冠词,eg:He acts as mangier. 他担任总经理。
One of his friends acted as go-between. 他的一个朋友担任/扮演中间人。
③accept the invitation 接受邀请④water前不加the,eg:Being heated, water will become vapour.⑤朝代前加定冠词the⑥take action 中间不加冠词,action也不用复数形式⑦位于句首的名词前不能加冠词,如:Child as he is, he knows a lot.1.“Do you know ___ English for ‘帅哥’?” “I’m afraid I don’t. I’m not interested in __ English language.”A. the; theB. the; /C. /; theD. /; /陷阱:容易误选D,认为表示语言的名词前通常不用冠词。
分析:答案为A。
在英语中,表示语言的名词前通常不用冠词,但在某些特殊情况下可以用冠词。
如:(1)当语言名词表示特指含义,其前可加冠词。
如:The English spoken in America and Canada is a little different from that spoken in England. 美国和加拿大讲的英语与英国讲的英语有点不同。
(2)当语言名词表示某一语言中的对应词时,其前要用定冠词the。
如:What’s the English for this? 这个东西用英语怎么说?(3)当在语言名词后加上language一词时,也要用冠词。
备战2021高考英语热点题型和提分秘籍 专题04 形容词和副词(解析版) Word版含解析

专题四形容词和副词【高频考点解读】形容词和副词在高考试题中始终占很重要的地位。
近几年高考对形容词和副词的考查具有“淡化语法、留意深层语义”的特点,以形容词和副词辨析为热点。
同时连续加强对形容词和副词比较等级的考查。
其考点主要包括:1.考查形容词和副词词义辨析。
如:rather, still, such, surprised, surprising, therefore, though, too, very, yet 等。
2.考查形容词修饰名词时的词序,即指示代词/不定代词+数词(序数词、基数词)+描绘性形容词(nice, good, interesting, beautiful等)+特征性形容词(大小、长短、凹凸、外形、年龄、新旧)+颜色形容词+国籍、出处+物质、材料+用途、类别+中心名词。
3.考查形容词和副词比较等级的常用句型及其修饰成分在句中的位置。
如:三种常见的倍数表达法:(1)倍数+as+形容词或副词原级+as…;(2)倍数+the size/length/width/depth/height of…;(3)倍数+形容词或副词比较级+than+被比较对象。
4.考查与形容词和副词有关的习语结构。
如:more than, not more than, no more than, less than, not less than, no less than, other than, rather than,nothing else than“仅仅,只不过”,more than a little “格外,很”,more often than not “经常,在大多数状况下”,cannot(never, hardly)…too(enough)“无论……也不过分,越……越好”等。
2021年高考对形容词、副词的考查热点将仍旧集中在对形容词、副词的词义辨析上,同时连续加强对形容词、副词比较等级的考查。
【热点题型】题型一形容词作状语例1、Coming out of the station,he dragged himself home,__________.A.sleepily and tired B.sleepily and tiredlyC.sleepy and tired D.tiredly and sleepy【提分秘籍】形容词作状语表示伴随或说明主语所处的状态,并不表达动作的方式。
备战2021高考英语热点题型和提分秘籍 专题05 介词和介词短语(解析版) Word版含解析

专题五介词和介词短语【高频考点解读】介词和介词短语也是高考的一个必考点,每年都保持在一至两个题目,命题形式除了单项填空外还在完形填空、语法填空、短文改错中进行考查,其考点主要涉及常用介词的用法区分,介词与动词、名词、形容词等的常见搭配,介词在特定语境中的选用和介词短语的用法等。
把握介词必需要立足基本用法,广泛记忆,细心体会比较。
其考点主要包括:1.考查意义相同或相近,但使用范围不同的介词,如:in, on, at, for, to, by, after, before, about, over, above, with, without, under, beyond, through, throughout, against, among, between, besides, except等。
2.考查介词与名词、形容词和动词的各种搭配形式,如:与to搭配的有key, answer, visit, apology, introduction等;与in搭配的有interest, satisfaction, expert等;与on搭配的有mercy, congratulation, effect, influence等;与其他介词搭配的有prize for, respect for, victory over, struggle with等。
3.考查不同介词与名词、形容词搭配后的词义辨析,如:“in +名词”(in charge 主管,掌管,看管); “in +名词+介词”(in consequence of 由于,由于……的原因); “on +名词”(on guard在值勤); “at +名词”(at length 具体地,长时间); “beyond +名词”(beyond description难以形容); “out of +名词”(out of patience不耐烦); “under +名词”(under construction在建设中)等。
冠词、名词、代词、介词和介词短语-(2020-2024)高考英语真题分类汇编(新高考专用)(原卷版)
专题01 冠词、名词、代词、介词和介词短语五年(2020-2024)高考英语真题分类汇编(新高考专用)第一部分:冠词考点五年考情分布考点1 a(n)的用法2023新课标I卷a; 2021新课标I卷a。
考点2 the的用法2024新课标I卷the2023新课标II卷the;2022新课标I卷the;2022新课标II卷the;2020新课标II卷the2020新课标I卷pan前加the;2020新课标I卷the改成a。
一.命题趋向1.考查不定冠词a和an的区别。
2.考查使用不定冠词的基本用法。
3.考查使用不定冠词的固定搭配。
4.考查使用定冠词的基本用法。
5.考查使用定冠词的固定搭配。
二.技巧点拨技巧一注意泛指还是特指如果空格后的名词或“形容词+名词”前没有形容词性物主代词、不定代词、名词所有格或指示代词等限定词时很可能填冠词。
1.如果空格及后面的名词在文中第一次出现,可翻译成“一个(本、种等)”,一般填a/an;如果是前文已经提到过,可翻译成“这/那个,这/那些”,一般填the。
2.如果名词后有of短语、不定式、分词或从句等作定语时很可能填the。
技巧二注意固定搭配考点一:不定冠词a(n)1.(2023新课标I卷)The meat should be fresh with ________ touch of sweetness and the soup hot, clear and delicious.2.(2021新课标I卷)While you’re in China, Mount Huangshan is ________ must to visit!考点二:定冠词the3.(2024新课标I卷)Further, the Silk Route Garden around the greenhouse walks visitors through a journey influenced by the ancient Silk Road, by which silk as well as many plant species came to Britain for ________ first time.4.(2024年浙江1月卷)Over the last two years, some supermarkets have started selling chicken or salad in packs designed with two halves containing separate portions(份). Then, when you use one section, ________ other stays fresh.5.(2023新课标II卷)Not the pandas, even though ________ language used for the medical training instructions is actually English.6.(2023浙江1月卷)In contrast to the court life and upper-class culture represented by the Forbidden City, the Summer Palace, and the Temple of Heaven, the hutongs reflect ________ culture of grassroots Beijingers.7.(2022新课标I卷)Covering an area about three times ________ size of Yellowstone National Park, the GPNP will be one of the first national parks in the country.8.(2022新课标II卷)________ Brown family live in an apartment building outside Toronto.9.(2022年浙江1月)Cobb, for her party, started to ask conference organizers who invited her to speak if she could do so remotely; about three-quarters of ________ time, they agreed.10.(2021浙江卷)________ Lincolns enlarged the house to a full two stories in 1856 to meet the needs of their growing family.11.(2020新课标II卷)The plum trees are ________ first to flower even as the snow is melting (融化).12.(2020浙江卷)Then,with ________ rise of science,changes began.第二部分:名词考点五年考情分布考点1动词/名词转换为名词2024新课标I卷--engineering; 2023新课标II卷--arrival;2021新课标II卷--representative;2020新课标II卷--celebration考点2形容词转换为名词2024新课标I卷--richness; 2020新课标I卷--interest; 2020新课标III卷--curiosity; 2020新课标卷--accuracy。
备战2021高考理数热点题型和提分秘籍 专题03 充分条件、必要条件与命题的四种形式(解析版)
专题三 充分条件、必要条件与命题的四种形式【高频考点解读】1.了解规律联结词“或”、“且”、“非”的含义.2.理解全称量词与存在量词的意义.3.能正确地对含有一个量词的命题进行否定. 【热点题型】题型一 含有规律联结词的命题的真假推断【例1】在一次跳伞训练中,甲、乙两位学员各跳一次.设命题p 是“甲降落在指定范围”,q 是“乙降落在指定范围”,则命题“至少有一位学员没有降落在指定范围”可表示为( )A .(綈p )∨(綈q )B .p ∨(綈q )C .(綈p )∧(綈q )D .p ∨q【提分秘籍】正确理解规律联结词“或”、“且”、“非”的含义是关键,解题时应依据组成各个复合命题的语句中所消灭的规律联结词进行命题结构与真假的推断.其步骤为:①确定复合命题的构成形式;②推断其中简洁命题的真假;③推断复合命题的真假.【举一反三】已知命题p :∃x ∈R ,cos x =54,命题q :∀x ∈R ,x 2-x +1>0,则下列结论正确的是( )A .命题p ∧q 是真命题B .命题p ∧綈q 是真命题C .命题綈p ∧q 是真命题D .命题綈p ∨綈q 是假命题解析:由余弦函数的值域知命题p 不正确;由于x 2-x +1=⎝⎛⎭⎫x -122+34>0,故命题q 正确.故选C. 答案:C 【热点题型】题型二 全称命题、特称命题的真假推断 【例2】下列命题中是假命题的是( ) A .∃α,β∈R ,使sin (α+β)=sin α+sin β B .∀φ∈R ,函数f (x )=sin(2x +φ)都不是偶函数C .∃m ∈R ,使f (x )=(m -1)·xm 2-4m +3是幂函数,且在(0,+∞)上单调递减D .∀a >0,函数f (x )=ln 2 x +ln x -a 有零点【提分秘籍】1.全称命题真假的推断方法(1)要推断一个全称命题是真命题,必需对限定的集合M 中的每一个元素x ,证明p (x )成立. (2)要推断一个全称命题是假命题,只要能举出集合M 中的一个特殊值x =x 0,使p (x 0)不成马上可. 2.特称命题真假的推断方法要推断一个特称命题是真命题,只要在限定的集合M 中,找到一个x =x 0,使p (x 0)成马上可,否则这一特称命题就是假命题.【举一反三】下列命题中的假命题是( ) A .∃x ∈R ,sin x =52B .∃x ∈R ,log 2x =-1C .∃x ∈R ,⎝⎛⎭⎫12x>0D .∀x ∈R ,x 2≥0解析:易知|sin x |≤1,故A 是假命题. 答案:A 【热点题型】题型三 含有一个量词的命题否定【例3】设x ∈Z ,集合A 是奇数集,集合B 是偶数集,若命题p :∀x ∈A,2x ∈B ,则( ) A .綈p :∀x ∈A,2x ∉B B .綈p :∀x ∉A,2x ∉B C .綈p :∃x ∉A,2x ∈BD .綈p :∃x ∈A,2x ∉B【解析】由于任意都满足的否定是存在不满足的,所以选D. 【答案】D 【提分秘籍】对含有一个量词的命题进行否定的方法:一般地,写含有一个量词的命题的否定,首先要明确这个命题是全称命题还是特称命题,并找到其量词的位置及相应结论,然后把命题中的全称量词改成存在量词,存在量词改成全称量词,同时否定结论.【举一反三】若命题p :∀x ∈⎝⎛⎭⎫-π2,π2,tan x >sin x ,则命题綈p :( ) A .∃x 0∈⎝⎛⎭⎫-π2,π2,tan x 0≥sin x 0 B .∃x 0∈⎝⎛⎭⎫-π2,π2,tan x 0>sin x 0 C .∃x 0∈⎝⎛⎭⎫-π2,π2,tan x 0≤sin x 0 D .∃x 0∈⎝⎛⎭⎫-∞,-π2∪⎝⎛⎭⎫π2,+∞,tan x 0>sin x 0 解析:∀x 的否定为∃x 0,>的否定为≤,所以命题綈p 为∃x 0∈⎝⎛⎭⎫-π2,π2,tan x 0≤sin x 0. 答案:C 【热点题型】题型四 利用全称(特称)命题的真假求参数范围【例4】若命题p :∃x ∈R ,ax 2+4x +a <-2x 2+1是假命题,则实数a 的取值范围是________.【提分秘籍】解题模板第一步:转化:依据条件命题的真假进行转化 其次步:求范围:依据转化问题,数形结合求参数范围 第三步:结论:回答问题结论第四步:反思:反思解题过程,留意端点值验证取舍 【举一反三】设集合A ={ (x ,y )|(x -4)2+y 2=1},B ={(x ,y )|(x -t )2+(y -at +2)2=1},假如命题“∃t ∈R ,A ∩B ≠∅”是真命题,则实数a 的取值范围是________.【高考风向标】1.(2022·湖南卷)已知命题p :若x >y ,则-x <-y ,命题q :若x >y ,则x 2>y 2.在命题①p ∧q ;②p ∨q ;③p ∧(綈q );④(綈p )∨q 中,真命题是( )A .①③B .①④C .②③D .②④2.(2022·辽宁卷)设a ,b ,c 是非零向量,已知命题p :若a ·b =0,b ·c =0,则a ·c =0,命题q :若a ∥b ,b ∥c ,则a ∥c ,则下列命题中真命题是( )A .p ∨qB .p ∧qC .(綈p )∧(綈q )D .p ∨(綈q )3.(2022·新课标全国卷Ⅰ) 不等式组⎩⎪⎨⎪⎧x +y ≥1,x -2y ≤4的解集记为D ,有下面四个命题:p 1:∀(x ,y )∈D ,x +2y ≥-2,p 2:∃(x ,y )∈D ,x +2y ≥2, p 3:∀(x ,y )∈D ,x +2y ≤3, p 4:∃(x ,y )∈D ,x +2y ≤-1. 其中的真命题是( ) A .p 2,p 3 B .p 1,p 2 C .p 1,p 4 D .p 1,p 34.(2021·重庆卷)命题“对任意x∈R,都有x2≥0”的否定为()A.对任意x∈R,都有x2<0B.不存在x∈R,使得x2<0C.存在x0∈R,使得x20≥0D.存在x0∈R,使得x20<0【答案】D【解析】依据定义可知命题的否定为:存在x0∈R,使得x20<0,故选D.【随堂巩固】1.命题“全部奇数的立方都是奇数”的否定是()A.全部奇数的立方都不是奇数B.不存在一个奇数,它的立方是偶数C.存在一个奇数,它的立方是偶数D.不存在一个奇数,它的立方是奇数解析:全称命题的否定是特称命题,即“存在一个奇数,它的立方是偶数”.答案:C2.已知命题p:∃x0∈R,x20+2x0+2≤0,则綈p为()A.∃x0∈R,x20+2x0+2>0B.∃x0∈R,x20+2x0+2<0C.∀x∈R,x2+2x+2≤0D.∀x∈R,x2+2x+2>0解析:依据特称命题的否定,特称量词改为全称量词,同时把不等号改为大于号,选择D.答案:D3.给出命题p:直线l1:ax+3y+1=0与直线l2:2x+(a+1)y+1=0相互平行的充要条件是a=-3;命题q:若平面α内不共线的三点到平面β的距离相等,则α∥β.对以上两个命题,下列结论中正确的是() A.命题“p∧q”为真B.命题“p∨q”为假C.命题“p∨綈q”为假D.命题“p∧綈q”为真4.给定命题p:函数y=sin⎝⎛⎭⎫2x+π4和函数y=cos ⎝⎛⎭⎫2x-3π4的图象关于原点对称;命题q:当x=kπ+π2(k∈Z)时,函数y=2(sin 2x+cos 2x)取得微小值.下列说法正确的是()A.p∨q是假命题B.綈p∧q是假命题C.p∧q是真命题D.綈p∨q是真命题5.已知命题p:“∀x∈[0,1],a≥e x”;命题q:“∃x0∈R,x20+4x0+a=0”.若命题“p∧q”是假命题,则实数a的取值范围是()A.(-∞,4] B.(-∞,1)∪(4,+∞)C .(-∞,e)∪(4,+∞) D.(1,+∞)6.已知命题p:∃x∈R,x2+1<2x;命题q:若mx2-mx-1<0恒成立,则-4<m≤0,那么()A.“綈p”是假命题B.“綈q”是真命题C.“p∧q”为真命题D.“p∨q”为真命题7.下列说法中,正确的是()A .命题“若am 2<bm 2,则a <b ”的逆命题是真命题B .命题“p ∨q ”为真命题,则命题“p ”和命题“q ”均为真命题C .已知x ∈R ,则“x >1”是“x >2”的充分不必要条件D .命题“∃x ∈R ,x 2-x >0”的否定是:“∀x ∈R ,x 2-x ≤0”8.已知f (x )=2mx 2-2(4-m )x +1,g (x )=mx ,若同时满足条件:①∀x ∈R ,f (x )>0或g (x )>0; ②∃x ∈(-∞,- 4),f (x )g (x )<0. 则实数m 的取值范围是________.9.命题p :若a ,b ∈R ,则ab =0是a =0的充分条件,命题q :函数y =x -3的定义域是[3,+∞),则“p ∨q ”、“p ∧q ”、“綈p ”中是真命题的有________.解析:依题意p 假,q 真,所以p ∨q ,綈p 为真. 答案:p ∨q ,綈p10.若命题“∀x ∈R ,ax 2-ax -2≤0”是真命题,则实数a 的取值范围是________.解析:当a =0时,不等式明显成立;当a ≠0时,由题意知⎩⎪⎨⎪⎧a <0,Δ=a 2+8a ≤0,得-8≤a <0.综上,-8≤a ≤0.答案:[-8,0)11.已知命题p :“∀x ∈N *,x >1x ”,命题p 的否定为命题q ,则q 是“________”;q 的真假为________(填“真”或“假”).解析:q :∃x 0∈N *,x 0≤1x 0,当x 0=1时,x 0=1x 0成立,故q 为真.答案:∃x 0∈N *,x 0≤1x 0真12.若命题“存在实数x 0,使x 20+ax 0+1<0”的否定是假命题,则实数a 的取值范围为________. 解析:由于命题的否定是假命题,所以原命题为真命题,结合图象知Δ=a 2-4>0,解得a >2或a <-2. 答案:(-∞,-2)∪(2,+∞)13.若∃θ∈R ,使sin θ≥1成立,则cos ⎝⎛⎭⎫θ-π6的值为________.14.已知命题p :∃a 0∈R ,曲线x 2+y 2a 0=1为双曲线;命题q :x -1x -2≤0的解集是{x |1<x <2}.给出下列结论:①命题“p ∧q ”是真命题;②命题“p ∧(綈q )”是真命题;③命题“(綈p )∨q ”是真命题;④命题“(綈p )∨(綈q )”是真命题.其中正确的是________.15.下列结论:①若命题p :∃x 0∈R ,tan x 0=2;命题q :∀x ∈R ,x 2-x +12>0.则命题“p ∧(綈q )”是假命题;②已知直线l 1:ax +3y -1=0,l 2:x +by +1=0,则l 1⊥l 2的充要条件是ab=-3;③“设a 、b ∈R ,若ab ≥2,则a 2+b 2>4”的否命题为:“设a 、b ∈R ,若ab <2,则a 2+b 2≤4”. 其中正确结论的序号为________.(把你认为正确结论的序号都填上)16.写出下列命题的否定,并推断真假.(1)q :∀x ∈R ,x 不是5x -12=0的根; (2)r :有些素数是奇数; (3)s :∃x 0∈R ,|x 0|>0.解析:(1)綈q :∃x 0∈R ,x 0是5x -12=0的根,真命题. (2)綈r :每一个素数都不是奇数,假命题. (3)綈s :∀x ∈R ,|x |≤0,假命题.17.写出由下列各组命题构成的“p ∨q ”,“p ∧q ”,“綈p ”形式的新命题,并推断其真假. (1)p :2是4的约数,q :2是6的约数;(2)p :矩形的对角线相等,q :矩形的对角线相互平分;(3)p :方程x 2+x -1=0的两个实根的符号相同,q :方程x 2+x -1=0的两实根的确定值相等.18.已知c >0,且c ≠1,设p :函数y =c x 在R 上单调递减;q :函数f (x )=x 2-2cx +1在⎝⎛⎭⎫12,+∞上为增函数,若“p ∧q ”为假,“p ∨q ”为真,求实数c 的取值范围.解析:∵函数y =c x 在R 上单调递减,∴0<c <1. 即p :0<c <1,∵c >0且c ≠1,∴綈p :c >1. 又∵f (x )=x 2-2cx +1在⎝⎛⎭⎫12,+∞上为增函数, ∴c ≤12.即q :0<c ≤12,∵c >0且c ≠1,∴綈q :c >12且c ≠1.又∵“p ∨q ”为真,“p ∧q ”为假, ∴p 真q 假或p 假q 真.①当p 真,q 假时,{c |0<c <1}∩⎩⎨⎧⎭⎬⎫c ⎪⎪c >12且c ≠1 =⎩⎨⎧⎭⎬⎫c ⎪⎪12<c <1. ②当p 假,q 真时,{}c | c >1∩⎩⎨⎧⎭⎬⎫c ⎪⎪0<c ≤12=∅ 综上所述,实数c 的取值范围为⎩⎨⎧⎭⎬⎫c ⎪⎪12<c <1.。
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专题二冠词【高频考点解读】冠词的考查几乎每年都有一两道题,而且基本都设两空。
一般状况下,试题的情景较为曲折,句式以复合句为主。
另外,在短文改错和语法填空中也经常涉及冠词的考查。
考查要点主要包括:1.考查定冠词和不定冠词的基本用法。
2.考查定冠词和不定冠词的特殊用法。
抽象名词具体化前冠词的使用状况、比较级前冠词的使用状况。
3.考查冠词的泛指、特指、类指和专指用法。
4.考查零冠词的运用。
另外,还涉及很多冠词与名词的固定搭配。
【热点题型】题型一不定冠词a,an用法例1、It is generally accepted that __________ boy must learn to stand up and fight like __________ man.A.a;a B.a;theC.the;the D.a;/【提分秘籍】1.不定冠词a(n)表示“某一个”,相当于some,译为“一个”。
2.不定冠词a(n)用于抽象名词前,意为“一种……的人或事”。
3.不定冠词a(n)用于有形容词修饰的一日三餐前。
4.不定冠词a(n)用于有形容词修饰的季节、日期前。
5.“a/an+序数词”不表示排序,表“又一、再一”。
6.不定冠词a(n)用于形容词最高级前无比较含义,表示程度,意为“很,格外”。
7.用于固定搭配中,如:as a matter of fact,in a hurry,in a word,have a (an)...knowledge of,have a (an)...understanding of,a waste of,a variety of,quite a few,in a way,all of a sudden,live a(an)+adj.+life 等。
【举一反三】Many people agree that ________ knowledge of English is ________ must in international trade today.A.a;a B.the;aC.the;the D./;the【热点题型】题型二定冠词the的用法例2、—Hi,Wang Xin! What attracts you so much in today's Jinling Evening News?—I'm quite impressed by __________ latest news that ______ senior citizens can enjoy free fares.A.a;the B./;theC.the;/ D.the;the【提分秘籍】1.用在世界上独一无二的人或物、自然现象、表示方位或表示创造物等的名词前。
2.用在序数词和形容词最高级前面。
3.用在乐器名词前,特殊是西洋乐器。
4.用在表示计量的名词前,如by the hour,by the day,by the dozen,by the yard 等,但是如表示单位的名词为不行数名词,之前不用冠词,如by weight/volume等。
5.用在表示某世纪、年月、时期或朝代的名词前。
6.用在上文已消灭过或说话双方都生疏的事物前,表示物指意义。
【举一反三】Tom works in a company and gets paid by __________ hour,totally 5,000 yuan __________ month.A.the;the B.a;theC.the;a D.a;a【热点题型】题型三零冠词的用法例3、Sam has been appointed __________ manager of the engineering department to take __________ place of George.A./;/ B.the;/C.the;the D./;the【提分秘籍】1.连系动词turn后作表语的单数可数名词不用冠词,但名词前若有形容词作定语时,则通常加冠词。
2.as/though引导的让步状语从句中,假如作表语的名词置于句首,习惯上单数名词前不用冠词。
3.在某些独立主格结构,如“单数名词+介词短语”中,名词前不用冠词。
4.no与such连用时应放在such之前,such后的名词不用冠词。
5.一个兼多种身份的状况,只在第一个名词前使用冠词,其他名词前不再使用冠词,如a clerk and writer (职员兼作家)。
6.称呼语及表示独一无二的头衔、职务的名词作宾语补足语、主语补足语、表语及同位语时,不加冠词,常用名词有king,president,chairman,monitor,head等。
【举一反三】The furniture,with its modern style and bright colors,suits modern houses and their gardens,but looks__________ in the garden of a traditional home.A.out of question B.out of orderC.out of sight D.out of place【高考风向标】1.(2022江西卷)22. They chose Tom to be ___captain of the team because they knew he was __smart leader.A. a; theB. the; theC. the; aD. a; a2.(2022陕西卷)19. ________ village where I was born has grown into ________ town.A. The; aB. A; theC. The; theD. A; a3.(2022天津卷)8. Life the like ________ ocean; Only ________strong-willed can reach the other shore.A. an; theB. the; aC. the ;/D. / ; a4.(2022浙江卷)2. The paper is due next month, and I am working seven days ______ week, often long into______night.A. a; theB. the; 不填C. a; aD. 不填;the5.(2022重庆卷)6.I can’t tell you ____ way to the Wilsons' because we don’t have_____ Wilson here in the village.A.the;aB.a; /C. a; theD.the ; /(2021·新课标I卷)31. India attained ________ independence in 1947, after _______ long struggle.A. 不填; aB. the; aC. an; 不填D. an; theA (2021·新课标Ⅱ卷)13. Four and half hours of discussion took us up to midnight,and break for cheese,chocolate and tea with sugar.A.a;aB. the; theC.不填;theD.a;不填(2021·新课标Ⅱ卷)9. It may not be a great suggestion. But before _______ is put for ward, we’ll make do with it.A. a good oneB. a better oneC. the best oneD. a best one(2021·浙江)15.People develop______ preference for a particular style of learning at______ early age and these preferences affect learning.A.a; anB. a;不填C.不填;theD. the ;an(2021·大纲卷)33.Four and half hours of discussion took us up to midnight,and Break forcheese,chocolate and tea with sugar.A.a;aB. the; theC.不填;theD.a;不填(2021·大纲卷)28. The watch was very good, and he 20 percent down for it.A. a good oneB. a Better oneC. the Best oneD. a Best one(2021·福建卷)21. T he "Chinese Dream" is ____ dream to improve people's well-being and ____ dream of harmony, peace and development.A. the; aB. a; aC. a; theD. the; the(2021·江西卷)32. A nimals are obviously ______ lower form of life than _______ man.A. a ; /B. the ; theC. a ; theD. / ; /(2021·山东卷)22. It was ______ cold winter night and the moon was shining brightly across ____ night sky.A. 不填;aB. a; theC. the; aD. the; 不填(2021·重庆卷)32. The parents were shocked by______news that their son needed______operation on his knee.A. A; /B. the; /C. the; anD. a; an【随堂巩固】1. He missed ______ gold in the high jump, but will get _____ second chance in the long jump.A. the; theB. /; aC. the; aD. a; /2. We are said to be living in ____ Information Age, ____ time of new discoveries and great changes.A. an; theB. 不填; theC. 不填; aD. the; a3. The development of industry has been_______ gradual process throughout _______ human existence, from stone tools to modern technology.A. 不填;theB. the; aC. a; 不填D. a; a4.The Smiths don’t usually stay at hotels, but last summer they spent a few days at a very nice hotel by________ sea.A./; a B.the; the C./; the D.the; a5. Carl is studying food science at college and hopes to open up meat processing factory of his own one day.A. / ;aB. / ;theC. the ; aD. the ; the6.Sam has been appointed _______ manager of the engineering department to take ____ place of George.A. /;/B. the;/ C the;the D./;the7. I woke up with bad headache, yet by evening the pain had gone.A. the; theB. the; anC. a; theD. a; an8. Sarah looked at finished painting with satisfaction.A.不填;aB. a; theC. the; 不填D. the; a9. Being able to afford _______ drink would be ______ comfort in those tough times.A. the; theB. a; aC. a; 不填D. 不填;a10.It is generally accepted that boy must learn to stand up and fight like man.A.a; aB.a; theC.the; theD.a; 不填11.As he reached front door, Jack saw strange sight.A. the;不填B. a; theC.不填aD. the; a12.Take your time—it’s just_____short distance from here to_____restaurant.A.不填;theB. a; theC. the; aD.不填;a13.Experts think that __________recently discovered painting may be ________ Picsso.A.the ;不填B. a ;theC. a ; 不填D. the; a14.Dr.Peter Spence, headmaster of the school, told us, “fifth of pupils here go on to study at Oxford and Cambridge.”A. 不填;AB.不填;TheC.the; TheD.a; A15.In communication, a smile is usually __________ strong sign of a friendly and _______ open attitude.A. the, /B. a, anC. a, /D. the, an16.As is known to all, People’s Republic of China is biggest developing country in the world.A.the ;不填B. 不填;theC. the ;theD. 不填;不填17.——It’s said John will be in a job paying over $60,000 _____ year.—— Right, he will also get paid by _____ week.A. the; theB. a; theC. the; aD.a; a18.Last year I had ________ narrow escape, and I don't want to risk my life ________ second time.A.the; the B.a; /C.a; a D.the; a19.—John, there's ________ certain Mrs.Myles on ________ phone for you.—Oh, I'm coming.Thank you.A.a; / B./; /C./; the D.a; the20.Christmas is ________ special holiday when ________ whole family are supposed to get together.A.the; the B.a; theC./; a D.a; /21.It came as ________ shock that ________ fire broke out in Shanghai yesterday, killing at least 5 people.A.a; a B.a; /C./; a D.the; the22.Most scientists seem to agree that ________ certain limit should be set on ________ consumption of cars to ease air pollution.A.a; the B./; theC.the; / D.the; the23.It is said that ________ wool produced in Australia is of ________ high quality.A./; / B.the; /C.the; a D.the; the24.—How do you find the guy who took ________ office last week?—He's always finding ________ fault with others.A./; a B.the; aC./; / D.the; /25.—What do you think we should do when ________ earthquake happens?—In my opinion, go to ________ open space away from buildings or trees.A.an; an B.the; anC.an; the D.the; the26.I started as ________ office clerk, and turned ________ department manager three years later.A.the; the B.an; aC.an; / D.the; /27.Jogging every morning is ________ good habit.Stick to it, and you'll make ________ great progress.A.a; / B.a; aC.the; a D./; /28.用适当的冠词填空Villages in developing countries often lack many things.Books.Clean water.Electricity.These shortages are easy to see.But __1__ different kind of shortage is not easy to see.That is __2__ shortage of experts.Many villages have no doctors,engineers or scientists.They have no one who knows how to treat unusual medical problems or design __3__ new energy system.There is __4__ way to ease __5__ problem.You can do it with computers.In __6__ past few years,computer scientists around __7__ world have developed what they call “expert systems”.__8__ expert system is__9__ special kind of computer program.In some situations,it can take __10__ place of a human expert.。