if 的用法
I
if
［误］ If it will rain I won't go to school tomorrow.
［正］ If it rains I won't go to school tomorrow.
［析］由if引起的状语从句要用一般时表示将来。
［误］ I want to know if he comes here tomorrow.
［正］ I want to know if he will come here tomorrow.
［析］ if所引起的如果是宾语从句则不能用一般现在时表示将来。
［误］ I want to know if it will rain tomorrow he will come or not.
［正］ I want to know if it rains tomorrow he will come or not.
［析］这里的if从句是整个宾语从句的条件状语，所以，还应用一般时表示将来。
ill
［误］ He spent many years looking after his ill father.
［正］ He spent many years looking after his sick father.
［析］ ill和sick都可以作表语，如： I'm ill (sick). 美国英语中常用sick，而英国英语中两者都可用，但ill一般不作定语。
in
［误］ In a cold morning, I went to school alone.
［正］ On a cold morning, I went to school alone.
［析］在in the morning或in the afternoon词组中，不论在这两个名词的前或后加任何修饰词，其介词in都要变为on.
［误］ I will finish it after two days.
［正］ I will finish it in two days.
［析］中文中几天以后可以完成，或几天后来取，在译为英文时都不要用after，而要用in.如： He will be back in a few days.
in into
作为副词应用in，而不能用into，如： Come in, please. 又若在句中不涉及到动词
的位置，只是表达空间的位置时用in，如： The teacher in the office is my mother. 但在go, run, come, walk, dive等词后则要用into. 如： She dives into the river.
instead
［误］ The boy stayed in bed all day instead to go to school.
［正］ The boy stayed in bed all day instead of going to school.
［析］ instead of其后要接动名词、名词或代词，而不能用不定式，如： I choose this book instead of that one.
［误］ The beer here is not good, so I drink wine instead of it.
［正］ The beer here is not good, so I drink wine instead.
［析］ instead是副词，而instead of是介词短语。如： If you are not free, you may come another day instead.
interest
［误］ He has a great interest for physics.
［正］ He has a great interest in physics.
［误］ He has some interest in many companies.
［正］ He has some interests in many companies.
［析］ interest作为"兴趣"讲可用作不可数名词，但作为"利息"、"股份"讲时为可数名词。
［误］ This is an interested book.
［正］ This is an interesting book.
［析］修饰物时应用interesting, 如，an interesting film，而讲某人对某事感兴趣时要用过去分词interested，如： I'm interested in this play. 但"他是一个十分有趣的人"。应译为He is an interesting man. 所以interesting是"令人感兴趣"之意，而interested则表示某人对某事物感兴趣，多用"be interested in something"这一句型。
invent
［误］ America was invented by Christopher Columbus in 1492.
［正］ America was discovered by Christopher Columbus in 1492.
［析］ invent意为"发明"即从无到有，如： Compass was invented by the Chinese people. 而discover则意为"发现"。
it
［误］ That takes me ten years to finish this work.
［正］ It takes me ten years to finish this work.
［析］ it在这个句中的语法作用是形式主语，而真正的主语是句子后面的不定式。有的句子要用it作形式主语或形式宾语，如： I think it difficult to learn English well.
Ｊ
join
［误］ Did you attend the football club?
［正］ Did you join the football club?
［析］ join经常用于参加某个团体、政党，并作为其中的一个成员；attend则重点强调出会议、到场，而不一定进行具体活动，如： Did you attend the meeting yesterday?而take part in则强调参与某些具体活动或运动，如： I take part in the football game.
just
［误］ I have finished my work just now.
［正］ I finished my work just now.
［析］ just now意义"刚才"，所以句中的谓语动词要用过去式。
［误］ Just I won the game.
［正］ I just won the game.
［析］ just单独使用时不应放在句首，而应放于① be动词之后，如： He is just a student.② 名词与一般动词之间。③ 用在第一助动词之后，如： I have just returned
home. 但just与其他词组成词组时，如just now, just then, 则可用于句首和句尾。如： Just then he saw the bus coming.
just justly
just常用于三种含意：① 恰好，如：It's just five o'clock. ② 仅仅，相当于only, 如：I have just enough money to buy a dictionary. ③ 不久前，如： I just missed my old friend; He left a few minutes ago. 而justly其意为"公正的"，如：He was justly punished for his crimes.
Ｋ
keep
［误］ She was keeping something to her father.
［正］ She was keeping something from her father.
［析］ "对某人隐瞒某事"要用"keep something from somebody"句型。
［误］ He kept to repeat the word again and again.
［正］ He kept repeating the word again and again.
［析］ keep doing something为连续不断地做某事。有时可以与keep on doing something互换。它们的区别在于keep doing something意为该动作一直不停地在进行中，如： When the train started, she kept waving her hand. 而keep on doing something则表示该动作可能停停顿顿但却一直在进行中，如： He kept on making the same mistakes in grammar.
［误］ We must keep up the times.
［正］ We must keep up with the times.
［析］这句话意为"我们必须赶上时代"，keep up with是"赶上"之意，而keep up则是"坚持下去"的意思，如： Keep it up, don't stop now!
key
［误］ I lost the key of the door.
［正］ I lost the key to the door.
［析］英语中讲某某的东西一般要用of，而key, entrance, answer则多用to，如："门的钥匙"为key to the door, "高速公路入口"为entrance to the highway, "问题的答案"为the answer (key) to the question.
kind
［误］ This kind of books are not good.
［正］ This kind of books is not good.
［析］ kind在这种句式中应作为主语，如果讲Those kinds of books are very good. 则是正确的。
kind sort type
kind和sort为同义词，意为"种类"，而type则为"型号"，如： What type of this car do you want?(你想要这种车的什么型号?)
knock
［误］ Someone was knocking the door.
［正］ Someone was knocking at the door.
［析］ knock虽可以作及物动词，如： The car knocked a hole in the fence. 但作"敲门"讲一定要用作不及物动词： knock at (on) the door.
know
［误］ I want to know to play this game.
［正］ I want to know how to play this game.
［析］要注意英语中在不定式前加疑问代词或疑问副词的用法。如：I want to know how to do it / what to do / when to do it / where to go.
know know of
I know him.为"我很了解他。"而I know of him. 则为"我听说过他。"同样的用法还有hear和hear of这一词组。
by的用法总结
by的用法小结： 1、介词prep. 在…旁；靠近 · Our teacher was sitting by the window. 我们的老师正坐在窗户旁边。 · Stand by me! 站到我的身旁来！ · We spent our holiday by the sea. 我们在海边度假。 2、介词prep. 经过 · He walked by me without speaking. 他走过我的身旁，没有说话。 · My brother goes by the building every day. 我弟弟每天从这楼旁走过。 3、介词prep. 用；靠；通过 using (showing who or what did something) · I know it by heart. 我把它记在心头。 · They can read by touch. 他们可以通过手摸来阅读。 · By getting up early, I can have an hour for reading English in the morning. 靠起得早，我每天早晨有一小时时间阅读英语。 4、介词prep. 不迟于 not later than · I shall be back by 5 o'clock. 最迟五点我一定回来。 · How many English parties had you had by the end of last term? 到上学期末，你们举行了几次英语晚会？ 5、介词prep. 通过；沿着 through; along; over
· We came through the fields, not by the road. 我们是穿过田野而不是沿那条路来的。· to send a letter by post 通过邮局寄信 6、介词prep. （表示作者）被；由 word that shows the author, painter, etc. · Thirty divided by two is fifteen. 三十除以二得十五。 · The child was saved by a PLA man. 这孩子是由一位解放军战士救活的。 · This bridge was built by the soldiers. 这座桥是士兵们造的。 7、介词prep. （指交通等）乘；用 word that shows what kind of transport, etc. · The man came by bus. 那人是坐公共汽车来的。 · They went to Shanghai by air. 他们坐飞机去上海。 8、介词prep. 在…情况下；在…时间during · Do you prefer travelling by day or by night? 你喜欢在白天还是在夜晚旅行？ 9、介词prep. （表示部分）在…部位word that shows which part · She led the child by the hand. 她拉着孩子的手往前走。 10、副词adv. 在旁边
IF的用法
IF的用法 if是英语中出现频率很高的连词，并且它的用法也很多。学生感到很难掌握，为了让同学们更多更好地了解其用法及其语法功能。现结合教学中遇到的情况，予以归纳，以供参考。 一、if作为连词，引导条件状语从句，它表示的意思是“假如”“如果”等。在复合句中如果主句用将 来时，则if引导的状语从句用一般现在时。例如： 1. If itdoesn’train, we will go to the park next Sunday. 如果天不下雨，下周星期天我们将去公园。 2. If you ask him，he will help you．如果你求他，他将会帮助你。 二、if还可以引导让步状语从句。这时if当作“即使是”，“虽说”解。例如： 1. If she’s poor，at least she’s honest．虽说她很穷，但至少她还是诚实的。 2. If I am wrong，you are wrong，too．即使说我错了，那么你也不对。 3. I’ll do it, even if it takes me all the afternoon．虽然会花费我一下午的时间，我还是要做这事。 三、if作为连词还可以引导宾语从句。引导宾语从句时和whether意思相同。例如： 1. Lily asked if ／whether she liked it. 莉莉问她是否喜欢它。 2. She asked if ／whether they had a cotton one．她问是否他们有一件棉织的。 四、if引导时间状语从句，当if做“当”或“无论何时”解而不含有条件之义时，if从句中的时态与主句中的时态相同。例如： 1. If youmix yellow and blue，you get green．你将黄色与蓝色混合，便会得到绿色。 2. If she wants the servant，she rings the bell．每当她需要仆人时，她便按铃。 五、if后接否定动词，用于感叹句中，表示沮丧、惊奇等。例如： I. Well，if I haven’t left my false teeth at home!真倒霉，我把假牙丢在家里了! 2. And if he didn’t try to kn ock me down!(What do you think he did!He tried knock me down!)你猜他想做什么?他想把我撞倒! 六、用于虚拟语气中，if从句中用过去式，表示不可能实现，大概不会实现或提出作为考虑的假定条件。例如： 1. If you were a bird, you could fly.假使你是只鸟，你便会飞了。 2. If I asked him(if I were to ask him) for a loan，would he agree?如果我向他借贷，他会答应吗? 另外，if从句中用过去完成式，表示过去未实现的条件(例如由于不可能实现或某人之未能实行)。例如： 1. If they had startedearlier，they would have arrivedin time．要是他们早些动身，他们便可及时到达了。 2. If they had not started when they did，they would not be here now．如果他们那时不动身，现在他们就不会在此地了。 第三，在文学体栽中，if有时可省略，然后将主语与所用的限定动词(尤其是were，had，should)倒置。例如： 1. Should it (=if it should)be necessary，I will go. 倘若有必要，我会去的。 2. Were I(=if I were) in your place，I would do the same ．如果我处于你的位置，我也会这样干的。 3. Had I(=if I had)known earlier，I would come．如果我早一点知道，我就会来。 七、if与其它一些介词的连用。
excel公式中的If条件语句 如何在excel公式中的if使用and和or逻辑
excel公式中的if条件语句如何在excel公式中的if使用and和or逻辑 2007-12-27 因为本人从事教学工作，经常要用到Excel对成绩进行计算汇总，其中遇到的一个典型的问题是如何根据分数来给出优、良、中、差的等级。 如果只有两个分数段（如及格、不及格两个级别）很好办，假设成绩数据已经输入单元格A1，直接用Excel公式输入条件A1>=60，为真时填写“及格”，为假时填写“不及格”就可以了。这时显示在Excel 单元格里的公式是：=IF(A1>=60, “及格”,“不及格”)。 如果有多个分数段，比如要求: x<60-----------------------不及格 x>=60 AND x<75--------及格 x>=75 AND x<85--------良 x>=85----------------------优
其实很简单，只要了解Excel里IF函数参数和返回值的用法，第一个参数是条件，第二个参数是条件为真的返回值，第三个参数是条件为假的返回值；而且IF函数可以嵌套(根据Excel2003的帮助文件，最多嵌套可达七层)，这样上面的问题可以用如下公式来解决： =IF(A1<60,"不及格",IF(A1<75,"及格",IF(A1<85,"良","优"))) (这时无法使用Excel的交互式的方法输入，可以把这个公式修改后复制到单元格里) 因为Excel特有的单元格拖拽功能，很容易就把这个公式给复制到一整列上了，这样就实现了一系列成绩自动的给出等级，使用起来还是比较方便的。这个小技巧比较初级，但是我认为还是比较的实用的，见笑了。 (yanqlv原创，转载请注明出处） feng1725改进与完善： 成绩的正常值在0到100之间，大于0或小于100就是非法值，对此，我们对以上公式进行改进：
(完整版)time的用法总结
一. time的短语 from time to time 有时 on time 准时寸,in time 及时寸; all the time 始终，一直; at the same time 同时, ahead of time 提前 at no time 绝不 some time 一段时间 sometime在某一时候”可用来指过去或将来 sometimes （at times, from time to time）有时，不时” at a time （a time）
at one time （once） at times ( sometimes) in no time (immediately ) 立刻，马上; have a good/nice time (enjoy on eself) 过的愉快 for the time being 暂时” “ Many a time/many times 多次 take one ' s time容 kill time消磨时间 【活学活用】选出与画线部分意思相同或相近的选项 1. Jim comes to visit us from time to time. That' always the happiest time for the family. A. on time B. sometime
C. at times D. some times 2．At no time ______ study though __ ___great progress. A. should we give up; we have made B. shouldn 'w t e give up; we have made C. we should give up; we have made D. we shouldn 'g t ive up; have we made 3. ---When shall we visit the Science Museum?” --- ________ next week. ” A. Sometime B. Sometimes C. Some time D. Sometimes 答案：1. C2.A 3A 二．time 相关从属连词高考常考点 1. every time / each time 每次Every time I call on him, he is out.
英语中if的用法
精心整理1.(表示条件)如果,主句用将来时，if从句用现在时表示将来Hewillcomeifyouinvitehim. 如果你请他,他会来的。 2.(表示虚拟)假如,要是 1 a. b. 句型：条件从句主句 过去完成时should(would)have+过去分词 Ifshehadworkedharder,shewouldhavesucceeded. Thericewouldnothavebeenburntifyouhadbeenmorecareful.
IfmylawyerhadbeenherelastSaturday,hewouldhavepreventedmefromgoing. Ifhehadcomeyesterday,Ishould/wouldhavetoldhimaboutit. 含义：Hedidnotcomeyesterday,soIdidnottellhimaboutit. c. were+ Ifyousucceeded,everythingwouldbeallright. Ifyoushouldsucceed,everythingwouldbeallright. Ifyouweretosucceed,everythingwouldbeallright.
3.是否=whether连接宾语从句 Iwonderifsheisill. 不知她是否病了。 连接词conj. 1.( 2.( 3.( 4.是否 不知她是否病了。 5.(表示因果关系)每一次...的时候(总是会) IfIfeelanydoubt,Iinquire. 我一感到有疑问就随时询问。 if作为连词的时候，一般用于条件状语从句或者是宾语从句或让步状语从句
If和+whether的用法讲课教案
If和whether if不能替换whether的5种情况 1.正式文体中，句中有or not 时 2.引起主语，表语，同位语从句时 3.作介词宾语时 4.放不定式前，与不定式组成词组时 5.作discuss等词的宾语时 以上是if和whether表示"是否"之意的区别，此外，if还有加入的意思，引起条件状语从句；而whether 另有不管无论之意，引起让步状语从句 whether与if作“是否”讲，在用法上有相同之处，也有不同之处。 一、相同之处。 1.whether和if都能引导宾语从句，常置于see,ask,learn,tell,wonder,doubt,find out等动词之后。 如：He asked me whether/is I could help him. I want to know whether/if he lives there. 2.whether和if都可用it作形式主语从句中。如：it's uncertain whether/if he'll come this evening. 3.在be uncertain/doubtful之后，常用whether引导宾语从句，有时也可以用if，如：We are uncertain whether/if Mary will come. 二、不同之处。 1.whether可置于句首引导主语从句，而if不能。如：___the 2000 Olympic Games will be in Beijing is not known yet. A.whether B.If C.Whether D.That 答案是C。 2.whether可用在介词之后，引导宾语从句，而If则不能。如：Success depends on whether we make evough effort. 3.whether可引导表语从句，if则不能。如：The puestion is whether it is not worthdoing. 4.在名词之后引导同位语从句时，用whether而不用if。如：The puestion whether the students answered correctly should be decided by the teacher. 5.whether后可接不定式，而if不能。如：Please tell us whether to go or stay here. 6.在有些动词（如discuss）之后，只能用whether，而不用if引导宾语从句。如：We discussed whether we should close the shop. 7.在引导否定概念in宾语从句时，只能用if，而不用whether.如：he asked me if I hadn't finished my work. whether和if都可以引导宾语从句，表示“是否”，在口语或间接引语中两者可以互换使用。如： I wonder if / whether I can get some advice from you. Ask him whether / if he can come. 但在有些情况下，whether和if的用法有一定区别。 1. whether引导的从句常可以与连词or或or not直接连用，而if一般不能。如： 正：Let me know whether you can come or not. 误：Let me know if you can come or not. 2. 当宾语从句提到句首时，只能用whether引导，而不能用if。如： 正：Whether it is true or not, I can’t tell. 误：If it is true or not, I can’t tell. 3. whether可以引导带to的不定式，if则不能。如： 正：I don’t know whether to accept or refuse.
with用法小结
with用法小结 一、with表拥有某物 Mary married a man with a lot of money . 马莉嫁给了一个有着很多钱的男人。 I often dream of a big house with a nice garden . 我经常梦想有一个带花园的大房子。 The old man lived with a little dog on the lonely island . 这个老人和一条小狗住在荒岛上。 二、with表用某种工具或手段 I cut the apple with a sharp knife . 我用一把锋利的刀削平果。 Tom drew the picture with a pencil . 汤母用铅笔画画。 三、with表人与人之间的协同关系 make friends with sb talk with sb quarrel with sb struggle with sb fight with sb play with sb work with sb cooperate with sb I have been friends with Tom for ten years since we worked with each other, and I have never quarreled with him . 自从我们一起工作以来，我和汤姆已经是十年的朋友了，我们从没有吵过架。 四、with 表原因或理由 John was in bed with high fever . 约翰因发烧卧床。 He jumped up with joy . 他因高兴跳起来。 Father is often excited with wine . 父亲常因白酒变的兴奋。 五、with 表“带来”，或“带有,具有”，在…身上，在…身边之意
if用法归纳
1. If you eat my food, I won’t talk to you. (P58) 2. I will die , I don’t have food, (P58) 3. What shall we do if it rains tomorrow? 5. She asked me if I was fond of music. 她问我是否喜欢音乐。 6. Can you tell me if they’re planning to come? 你能告诉我他们是否打算过来吗？ 7. I don’t know if she’s coming. 我不知道她是否会来。 ◇相关词组 ☆if you want/like如果你愿意的话 You can come and stay with us if you want. ☆if so如果是的话 Are you planning to return to work, and if so, who is going to look after the baby? ☆if not如果不是的话 Has anyone dealt with the technical problems? And if not, why not?☆if necessary/if possible 如果必要/可能的话 We are ready to fight for our rights if necessary. I should like to be back here by 10:30 if possible. ☆even if即使 I’d rather never sell this painting, even if they offered me a million dollars. ☆what if 要是……，那怎么办？如果……那会怎样？ What if the boss walked in here now and saw us? ☆as if好像是…… She always talks to me as if she was my sister. ◇相关练习 动词填空： 1. If it ______ (be) sunny tomorrow, I ______( walk) to school . 2. We ________ (not have ) our sports meeting if the
to 用法总结
be/get/become used to 习惯于 be related to 与…有关系 be addicted to 沉溺于；对…上瘾 be opposed to 反对 devote oneself to献身于；专心于 be devoted to 致力于；忠诚于 be admitted to 被…录取；准进入 be reduced to 沦为 reduce…to…使…沦为 be attached to附属于；喜欢；依恋 be adjusted to 适应 be sentenced to被判处 be exposed to 暴露于；遭受 be/become/ get accustomed to//accustomed to 惯于；有…习惯be engaged to 与…订婚 get down to 着手做 lead to 导致 object to反对；不喜欢；不赞成 give rise to 引起 stick to 坚持； see to 负责；注意 contribute to对…作贡献；有助于 make contributions to对…作贡献 apply oneself to 致力于 in addition to除…之外 turn to转向；求助于 look up to 尊敬 belong to 属于 take to 喜爱；开始 respond to 回答；对…作出回应 amount to等于 refer to 谈到；参考；查阅 turn a blind eye to对…视而不见 turn a deaf ear to 对…充耳不闻 show honour to向…表示敬意 propose a toast to 提议…… set fire to 放火烧…… occur to sb. 想起；想到 hold to 坚持；抓住 help oneself to 随便用…… hold on to 抓住；固守
if条件句和should的用法
If 引导条件句的用法 1、真实条件句用于陈述语气，假设的情况可能发生，其中if 是如果的意思。时态关系 句型：条件从句主句 一般现在时shall/will + 动词原形 If he comes, he will bring his violin. 典型例题 The volleyball match will be put off if it ___. A. will rain B. rains C. rained D. is rained 答案B。真实条件句主句为将来时，从句用一般现在时。 注意： 1）在真实条件句中，主句不能用be going to表示将来，该用shall, will. (错) If you leave now, you are never going to regret it. (对) If you leave now, you will never regret it. 2）表示真理时，主句谓语动词便不用shall (will) +动词原形，而直接用一般现在时的动词形式。 2 非真实条件句 1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。 a. 同现在事实相反的假设。 句型：条件从句主句 一般过去时should( would) +动词原形 If they were here, they would help you. b. 表示于过去事实相反的假设。 句型：条件从句主句 过去完成时should(would) have+ 过去分词 If she had worked harder, she would have succeeded. The rice would not have been burnt if you had been more careful. If my lawyer had been here last Saturday, he would have prevented me from going. If he had come yesterday, I should / would have told him about it. 含义：He did not come yesterday, so I did not tell him about it. If he had not been ill and missed many classes, he would have made greater progress. 含义：He was ill and missed many lessons, so he did not make greater progress. c. 表示对将来的假想 句型：条件从句主句 一般过去时should+ 动词原形 were+ 不定式would + 动词原形 should+ 动词原形
if、 whether 用法总结
whether,if if和whether通用，都表示“是否”的意思。一般来说，后者比较正式，在口语中前者常用来代替后者。但两者有时具有不同的暗示。用whether时，正反两面的选择意义较强，问话人并不在意回答是肯定还是否定；而用if时，则比较强调单方面，即正面，问话人希望得到肯定的回答。另外，还要注意以下几点： 一、whether和if都可以与or not连用；但写在一起时，只能用whether，不能用if。如： I don't care whether (或if) it will rain or not． I don't care whether or not it will rain. (不用if) 二、在引导宾语从句时，应注意： 1、表示“是否”时，两词都能引导宾语从句。 I wonder if/whether you can examine him now． 2、宾语从句移置句首时，用whether，不用if。
Whether it is true or not，I can't say． 3、宾语从句为否定形式时，通常用if，而不用whether。 I asked Tom if Mary wouldn’t come． 4、作discuss等词的宾语，用whether不用if。 We discussed whether we should buy the gift for him． 三、在下列情况下，只能用whether，不能用if。 1、与不定式连用时，只能用whether． He can't decide whether to accept or refuse． 2、在介词后，只能用whether。 Everything depends on whether he is ready． 3、在名词后作同位语时，只能用whether。
的用法总结
I t的用法总结 一. 代词: 1)指代上文 2)指代this/that 3)指代未知性别的婴儿或孩子或身份不明的人 4）指代时间/地点/天气/温度/距离/环境 1.It gets dark very early in the winter. 2.What will you call it if it’s a boy 3.I love spring---It’s a wonderful time of the year. 4.It’s less than 100 kilometres from here to Jinan. 5.When the factory closes, it will mean 500 people losing their jobs. 6.What’s this It’s a cat. 7.It has snowed much this year. (1)The book in your bag is very interesting. Can I borrow (2) The book in your bag is more interesting than ______ on the desk. (3) The weather here is much colder than____ in Nanjing. (4) The books are free. You can take____ free of charge. (5) The books in the bag are better than _____ on the desk.
if的用法
一、if作为连词，引导条件状语从句，它表示的意思是“假如”“如果”等。在复合句中如果主句用将来时，则if引导的状语从句用一般现在时。例如： 1. If itdoesn’train, we will go to the park next Sunday. 如果天不下雨，下周星期天我们将去公园。 2. If you ask him，he will help you．如果你求他，他将会帮助你。 二、if还可以引导让步状语从句。这时if当作“即使是”，“虽说”解。例如： 1. If she’s p oor，at least she’s honest．虽说她很穷，但至少她还是诚实的。 2. If I am wrong，you are wrong，too．即使说我错了，那么你也不对。 3. I’ll do it, even if it takes me all the afternoon．虽然会花费我一下午的时间，我还是要做这事。 三、if作为连词还可以引导宾语从句。引导宾语从句时和whether意思相同。例如： 1. Lily asked if ／whether she liked it. 莉莉问她是否喜欢它。 2. She asked if ／whether they had a cotton one．她问是否他们有一件棉织的。 四、if引导时间状语从句，当if做“当”或“无论何时”解而不含有条件之义时，if从句中的时态与主句中的时态相同。例如： 1. If youmix yellow and blue，you get green．你将黄色与蓝色混合，便会得到绿色。 2. If she wants the servant，she rings the bell．每当她需要仆人时，她便按铃。 五、if后接否定动词，用于感叹句中，表示沮丧、惊奇等。例如： I. Well，if I haven’t left my false teeth at home!真倒霉，我把假牙丢在家里了! 2. And if he didn’t try to knock me down!(What do you think he did!He tried knock me down!) 六、用于虚拟语气中，if从句中用过去式，表示不可能实现，大概不会实现或提出作为考虑的假定条件。例如： 1. If you were a bird, you could fly.假使你是只鸟，你便会飞了。 2. If I asked him(if I were to ask him) for a loan，would he agree?如果我向他借贷，他会答应吗? 七、if从句中用过去完成式，表示过去未实现的条件(例如由于不可能实现或某人之未能实行)。 1. If they had startedearlier，they would have arrivedin time． If they had not started when they did，they would not be here now． 第三，在文学体栽中，if有时可省略，然后将主语与所用的限定动词(尤其是were，had，should)倒置。例如： 1. Should it (=if it should)be necessary，I will go. 倘若有必要，我会去的。 2. Were I(=if I were) in your place，I would do the same ． 3. Had I(=if I had)known earlier，I would come．如果我早一点知道，我就会来。 八、if与其它一些介词的连用。 （1）as与if连用，它的意思是：“仿佛、好像”同样引导从句。例如： 1. It isn’t as if we are rich．(We are not rich．)我们不像富有的样子。(即我们不富有) 2. It isn’t as if he doesn’t know the ruler．(i．e．He does know the rulers．) （2）as if还可以引导感叹句。例如： As if I would allow it!(i．e．I would certainly not allow it!) （3）if与only连用。常表示愿望或一个未实现的条件，尤其用于感叹句中。例如： 1. If only he arrives in time!他若能及时到达就好了! 2. If only she would marry me!但愿她能嫁给我！ 3. If only she had known about it!（But she didn’t know.） 1.if 可引导状语从句----“如果...,假使...”[就现在,过去,未来可能实现之事加以推测时] If you are tired, we will go straight home 如果你疲倦了,我们就直接回家 If you have finished reading this book, please return it to me Do you mind if I open the window? 如果我打开窗子,你介意吗?
use_用法总结
use的用法小结 1. used to do sth.意为"过去常常做某事"，它表示过去经常发生的动作或存在的状态，而现在已不再发生或存在。这个短语含有今昔对比之意，其否定形式常用used not to或didn't use to。反意疑问句中应该用did/didn't或used/usedn't。例如： I used to swim in this river when I was young.我年轻时常在这条河里游泳。 They used to be good friends, didn't they?他们过去是好朋友，是吗？ 2. be used to sth. / doing sth.意为"习惯、适应某事/做某事"，它表示习惯于某一客观事实或状态，其中to是介词，后面跟名词、代词或动名词；be used可用于多种时态；如强调动作可用get或become替换be。例如： Old people are used to getting up early in the morning.老年人习惯早晨很早起床。 I wasn't used to city life, but now I have got used to living in this city.我以前不习惯都市生活，但现在我已习惯住在这座城市了。 3. be used to do sth.意为"被用来做某事"，其中use表"使用"之意，是被动语态形式，to是动词不定式符号。例如： Wood can be used to make paper.树木可以用来造纸。、 4. be used for...意为"被当做……",其中use表"使用"之意，是被动语态形式。例如： The seal's fur can be used for coats.海豹皮可当做大衣用。
IF函数的使用方法(入门级)
一、IF函数的使用方法（入门级） 1、单条件判断返回值 =IF(A1>20,"完成任务","未完成") 2、多重条件判断 =IF(A1="101","现金",IF(A1="1121","应收票据"，IF(A1=1403,"原材料"))) 注：多条件判断时，注意括号的位置，右括号都在最后，有几个IF就输入几个右括号。 3、多区间判断 =IF(A1<60,"不及格",IF(A1<80,"良好","优秀")) =IF(A1>=80,"优秀",IF(A1>=60,"良好","不及格")) 注：IF在进行区间判断时，数字一定要按顺序判断，要么升要不降。 二、IF函数的使用方法(进阶) 4、多条件并列判断 =IF(AND(A1>60,B1<100),"合格","不合格")
=IF(OR(A1>60,B1<100),"合格","不合格") 注：and()表示括号内的多个条件要同时成立 or()表示括号内的多个条件任一个成立 5、复杂的多条件判断 =IF(OR(AND(A1>60,B1<100),C1="是"),"合格","不合格") =IF(ADN(OR(A1>60,B1<100),C1="是"),"合格","不合格") 6、判断后返回区域 =VLOOKUP(A1,IF(B1=1,C:D,F:G),2,0) 注：IF函数判断后返回的不只是值，还可以根据条件返回区域引用。 三、IF函数的使用方法（高级） 7、IF({1,0}结构 =VLOOKUP(A1,IF({1,0},C1:C10,B1:B10),2,0) {=VLOOKUP(J15&K15,IF({1,0},A1:A2&B1:B2,C1:C2),2,0)} 注：利用数组运算返回数组的原理，IF（{1,0}也会返回一个数组，即当第一个参数为1时的结果放在第1列，为0时的结果放在数组第二列。
asif用法归纳
as if 用法归纳 1． as if 从句的作用?as if一般可由as though来代替。 引导表语从句，可在look, seem等系动词后。如： He looked as if / though he was ill. 他看起来好像生病了。It seems as if it is going to rain.看来好像要下雨了。 引导方式状语从句。如： I remember the whole thing as if / though it happened yesterday. The child talked to us as if he were a grown-up. 那个小孩跟我们讲话就像个大人一样。 2． as if 从句的语气及时态 ①as if从句用陈述语气。当说话者认为句子所述的是真实的或极有可能发生或存在的事实时， It sounds as if it is raining. 听起来像在下雨。 He talks as if he is drunk. 从他说话的样子来看他是醉了。 ②as if从句用虚拟语气。当说话人认为句子所述的是不真实的或极少有可能发生或存在的情况时， 表示与现在事实相反，谓语动词用一般过去式。如： You look as if you didn’t care. 你看上去好像并不在乎。When a pencil is partly in a glass of water, it looks as if it were broken． 表示与过去或与谈话时间为止发生的事实相反，谓语动词用
“had +过去分词”。如： He talked about the Great Wall as if he had been there before.说起长城来好像他以前去过那里。 The girl listened as if she had been turned to stone.女孩听着，一动也不动，像已经变成了石头。 表示与将来事实相反，谓语动词用“would / could / might + 动词原形”。如： He opened his mouth as if he would say something. 他张开嘴好像要说什么。 It looks as if it might snow.? 看来好像要下雪了。 3． as if从句中的省略。如果as if 引导的从句是“主语+系动词”结构，可省略主语和系动词等成份，这样as if 后就只剩下名词、不定式、形容词（短语）或动词-ing形式等。 He acts as if (he was) a fool.? 他做事像个傻子。 He paused as if (he was going) to let the sad memory pass. The girl left the room hurriedly as if (she was) angry.?女孩匆忙离开房间，好像生气的样子。 From time to time, Jason turned round as if (he was) searching for someone. 词汇学习 1. A smelly gas came out of the cracks.
英语中if的用法
1. (表示条件)如果,主句用将来时，if从句用现在时表示将来 He will come if you invite him. 如果你请他,他会来的。 2. (表示虚拟)假如,要是 1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。 a. 同现在事实相反的假设。 句型：主句 should( would) + If they were here, they would help you. b. 表示于过去事实相反的假设。 句型：主句 should(would) have+ 过去分词 If she had worked harder, she would have succeeded. The rice would not have been burnt if you had been more careful. If my lawyer had been here last Saturday, he would have prevented me from going. If he had come , I should / would have told him about it. 含义：He did not come , so I did not tell him about it. If he had not been ill and missed many classes, he would have made greater progress. 含义：He was ill and missed many lessons, so he did not make greater progress. c. 表示对将来的假想 句型：主句 should+ were+ would + should+ 动词原形 If you succeeded, everything would be all right. If you should succeed, everything would be all right. If you were to succeed, everything would be all right. 3. 是否= whether 连接 I wonder if she is ill. 不知她是否病了。