最新whether和if的用法区别

whether和if的用法区别

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 worth doing.

4.在名词之后引导同位语从句时，用whether而不用if。如：The question 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.

英语时态一般现在时表示现在、经常或习惯的动作或状态和普遍现象、常识或客观真理；一般过去时用于过去某一时间内发生的或过去习惯性的动作或状态；一般将来时表示将要发生的动作或存在的状态，将来打算做的事情；现在完成时表示过去发生的动作造成目前的结果和对现在造成的影响或表示从过去延续至今的动作、状态和习惯等；将来完成时表示将来某时之前业已完成或发生的事情；过去完成时表示过去某时间之前已经发生的动作或状况，即过去的过去。注意每一种时态与其他时态的交叉使用情况。英语共有十六种时态，其表现形式如下(以study为例)：

一般时进行时完成时完成进行时

study studies am studying is studying are studying have studied

has studied have been studying has been studying

studied was studying were studying had studied had been studying

shall study will study shall be studying will be studying shall have studied

shall have been studying will have been studying

should study would study should be studying would be studying

should have studied would have studied should have been studying would have been studying

但考试中出现的一般有以下几种。

第一节一般现在时

一、表示一般性或经常发生的动作或状态

二、表示习惯性动作和状态或普遍的现象或常识

三、表示客观事实、客观规律和客观真理。在宾语从句中，即使主句的谓语动词用了过去时，只要从句表示的是客观真理，从句的谓语动词也要用一般现在时

四、祈使句必须用动词原形，其否定结构用“don`t＋动词原形”，如：Go and fetch some water. ／Don`t do that.

五、在反义疑问句中，如果主句用肯定句，那么，反问句用否定形式；如果主句用否定形式，那么，反问句就用肯定形式。而且前后在时态上要一致。但祈使疑问句用won`t you?进行反问。如：See a film tonight, won`t you?

注：①祈使句后边可用附加疑问句，以加强语气。如果祈使句用肯定形式，附加疑问句用否定形式；如果祈使句用否

定形式，附加句用肯定形式；如：Come here next Sunday, won`t you? ／Don`t tell it to anyone, will you? ②但如果祈使句的前一句有了表示强烈肯定的语言环境，即使祈使句用了肯定形式，其附加成分也可以用“will you”(表示肯定，如果是在口语中用降调)。如：Give me the book, will you?

第二节一般过去时

一、一般过去时主要表示过去某一时刻发生的动作或情况，句中通常有表示过去某一时刻的状语a day ago, last week, in 1996, during the night, in anceint times等，表示“过多少时间之后”用after, 但在现在完成时中用in, 如in the past few years 等

第三节一般将来时

一、一般将来时表示将要发生的动作或状况

二、在表示时间和条件的状语从句中，一般现在时代替一般将来时。这些时间副词有when, as soon as等，表示条件的连词有if,as long as等

三、一些表示方向及变化的瞬间动词可用进行时或现在时表示将要发生的动作

We leave (are leaving) for California the day after tomorrow.我们(计划)后天动身去加利福尼亚州。

May I have your attention please. The plane for Wuhan is about to take off.请注意，飞往武汉的飞机就要起飞了。

四、另外，“be +to ＋动词原形”也可表示打算做的事，还可表示责任、意向和可能性

You are to follow the doctor’s advice.你应遵从医嘱。

No shelter was to be seen.找不到避难处。

第四节现在完成时

一、现在完成时的构成式是have(has)＋动词的ED分词

二、现在完成时表示到现在为止的一段时间内发生的情况或动作，强调的是对现在的影响，可能是已完成的动作，也可表示多次动作的总和，或习惯性的行为和持续的动作

三、如果句中有表示到现在为止这段时间的状语时，用现在完成时，这些时间状语有now, today, this week, this month, this year，现在完成时不和表示具体的时间状语连用，如yesterday, last year等，但可以和always, before, just, in／during the past(few weeks, years, fifty years)连用，这时in表示“过去多少时间”，不能用after

四、在有already, as yet, yet, ever, just, never 这类副词作状语的情况下，用现在完成时

五、有“since＋时间点，for＋一段时间”引导的状语时，主句谓语用现在完成时态

11) Jekyll Island has been one ［A］of Georgia’s state ［B］parks ［C］in ［D］1954.

12) He is ［A］in this country now ［B］for five years，but he makes ［C］no attempt to speak ［D］our language.

13) The Browns ［A］are living a hard ［B］life because Mr. Brown has been unemployed ［C］since ［D］half a year.

六、现在完成时用于将来的情况，即主语为一般将来时，时间和条件从句中的谓语用现在完成时(而不能用将来完成时)表示将来某时完成的动作

第五节将来完成时和过去完成时

一、将来完成时表示将来某时业已发生的动作和情况，或已经存在的状态

二、过去完成时表示在过去某一时刻之前业已发生了的动作或现象，句中通常会出现有表示过去某一时刻的时间状语

第六节进行时态

一、现在进行时表示现在或现阶段进行的动作，但也和always, constantly, forever等频度副词连用表示一个经常进行的动作或现在存在的状态

二、瞬间动词和一些表示状态及感觉的动词一般不用进行时，而用一般现在时或一般过去时代替。这些动词包括：appear(显然), arrive, be, come, desire, go, find, hate, hope, join, know, leave, like, love, join, possess, start, sail, see, suggest, taste, think(认为), understand等，类似的动词还有belong to，consist of，seem(似乎)等

三、过去完成进行时

过去完成进行时表示到过去的某一时间点或某一时间段里一直在进行的动作或行为

5) They received the parcel that they for a long time.

［A］expected ［B］have expected ［C］had been expecting ［D］had expected

There is a well known incident in one of Moliere′s plays, where the author makes the hero express unbounded delight on being told that he had been talking prose during the whole of his life.(93年翻译)

四、例题解析

1) D错。slow只有作为不及物动词用时才与up或down连用，表示“慢慢向上”或“慢慢向下”。所以我们说，这里的slow是动词而不是形容词，应将动词slow后边加上“ing”，改为(is) slowing down，构成现在进行时。

2) C错，改为are。

3) A错，改为saw。

4) D错，改为are。

英语高考专题复习讲与练（17）反意疑问句

反意疑问句是英语四大问句之一，它是由一个陈述句加上一个短问句而构成的。反意疑问句的基本构成形式是：陈述句+动词（肯定或否定）+主语？如：

①She often has lunch at school, doesn’t she? ②You don’t like sports, do you?

使用反意疑问句要注意以下若干对应规则：

一、反意疑问句中问句部分的动词与陈述部分的动词在语气上成相反的对应关系，即：

肯定+否定？否定+肯定？如：

①You can’t do it, can you? ②They are very late for the meeting, aren’t they?

二、反意疑问句中问句部分的动词与陈述部分的动词种类要对应一致。如：

①He has supper at home every day, doesn’t he? （不能用hasn’t he?）

②They have known the matter, haven’t they? （不能用don’t they?）

三、反意疑问句中问句部分的动词在时态上应和陈述部分的时态一致。如：

①They will go to town soon, won’t they?（不能用don’t they?或aren’t they?）

②He works very hard, doesn’t he?（不能用didn’t he?或won’t he?）

四、反意疑问句的陈述部分含有由un-, im-, in-, dis-, 等否定意义的前缀构成的词语时，陈述部分要视为肯定含义，问句部分用否定形式。如：

①Your father is unhappy, isn’t he?（不能用is he?）

②The man is dishonest, isn’t he? （不能用is he?）

③It is impossible to learn English without remembering more words, isn’t it?（不能用is it ?）

五、反意疑问句的陈述部分带有little, few, never, hardly, seldom等否定意义的词时，问句部分用肯定式。如：

①She never tells a lie, does she?（不用doesn’t she?）

②He was seldom late, was he?（不用wasn’t he?）

六、反意疑问句的陈述部分为I am……时，问句部分习惯上用aren’t I？表示。如：

I am a very honest man, aren’t I?

七、反意疑问句的陈述部分为I(We) think(believe, suppose, consider) + that从句时，问句部分的动词及主语与that从句内的动词和主语保持一致。如：

①I think that he has done his best, hasn’t he?

②We think that English is very useful, isn’t it? （不用don’t we?）

八、反意疑问句的陈述部分为I(We) don’t think(believe, suppose, consider)+ that从句时，从句为否定意义，问句部分的动词和主语仍与that从句保持一致且用肯定式。如：

①I don’t think that you can do it, can you? （不用do I?）

②We don’t believe that the news is true, is it? （不用do we?）

九、反意疑问句的陈述部分为非第一人称主语+ think(believe, suppose, consider) + that从句时，问句部分的动词和主语与陈述部分的主句动词和主语保持一致。如：

①They all think that English is very important, don’t they? （不用isn’t it?）

②He didn’t think that the news was true, did he? （不用wasn’t/ was it?）

十、反意疑问句的陈述部分为主语+said( told, reported, asked……) + that从句时，问句部分的动词和主语与陈述部分的主句动词和主语保持一致。如：

①They said that you had finished your work, didn’t they? （不用hadn’t you）

②Kate told you that she would go there, didn’t she? （不用wouldn’t she?）

十一、陈述部分的主语为不定代词something, anything, nothing, everything时，问句部分的主语用it。如：

①Something is wrong with the computer, isn’t it?②Nothing has happened to them, has it?

十二、陈述部分的主语为不定代词somebody(someone), anybody(anyone), nobody(no one), everybody(everyone)时，问句部分的主语用he或they，这时问句动词的数应和he或they一致。如：

①Someone has taken the seat, hasn’t he?②Everyone has done their best in the game, haven’t they?

十三、陈述部分为Let me……时，问句部分习惯上用shall I? 或will you?形式。如：

Let me have a try, shall I?(will you?)

十四、陈述部分为Let us……时，问句部分习惯上用will you?形式。如：

Let us stop to rest, will you?

十五、陈述部分为Let’s……时，问句部分习惯上用shall we?形式。如：

Let’s go home together, shall we?

十六、陈述部分用上述情况以外的祈使句时，问句部分一般用will you?形式表示请求，用won’t you？形式表示委婉请求或邀请。如：

①Do sit down, won’t you?/ will you? ②You feed the bird today, will you?

③Please open the window, will you?(won’t you?)

十七、陈述部分为否定祈使句时，问句部分一般用will you?形式。如：

Don’t make any noise, will you?

十八、陈述部分为There (Here) + be + 主语时，问句部分用动词+there(here)?形式。如：

①There are two cakes on the plate, aren’t there? ②Here is a story about Mark Twain, isn’t here?

十九、陈述部分用had better +原形动词表示建议时，问句部分用hadn’t +主语？形式。

①You’d better tell him about the matter, hadn’t you?②We had better do it by ourselves, hadn’t we?

二十、陈述部分用used to +主语时，问句部分用didn’t + 主语？或usedn’t +主语？形式。

①He used to live in the country, didn’t he?/usedn’t he?

②They used to be good friends, didn’t they?/usedn’t they?

二十一、陈述部分用must(may, might) + have + V-ed表示推测时，若句中带有明显的过去时间的状语，问句部分动词用过去时形式。如：

①He might have forgotten his pen in the classroom yesterday, didn’t he?

（不用mightn’t he?/ hasn’t he?）

②You must have got up late this morning, didn’t you?（不用mustn’t you?/haven’t you?）

二十二、陈述部分用must(may, might) + have + V-ed表示推测时，若句中没有带明显的过去时间的状语，问句部分动词用现在完成时形式。如：

①Everyone must have known the death of the waitress, haven’t they? （不用mustn’t they?）

②You must have worked there a year ago, didn’t you?（不用mustn’t you?/ haven’t you?）

二十三、陈述部分的主语为从句时，问句部分的主语一般用it代替，如：

①What he said is true, isn\'t it? （不用didn’t he?）

②Where we will build the dam has not been decided yet, has it? （不用won’t we?）

二十四、陈述部分的主语为动名词或不定式时，问句的主语用it代替。如：

①To do one good deed is easy for a person, isn\'t it?②Skating is your favorite sport, isn\'t it?

反意疑问句专题练习

1.I think they will go to town tomorrow, ________?

A.do I

B.don’t I

C.will they

D.won’t they

2.I don’t believe he can catch up with me, _________?

A.can he

B.can’t he

C.do I

D.don’t I

3.I’m sure that I will be well again, __________?

A.am I

B.aren’t I

C.will I

D.won’t I

4.I am afraid that he will not come, _______? A.am I B.aren’t I C.will he D.won’t he

5.They don’t believe you are wrong, _________?

A.are you

B.aren’t you

C.do they

D.don’t they

6.He thought you were Beijing, _________?

A.didn’t he

B.did he

C.weren’t you

D.were you

7.We told you that he would come tonight, _______?

A.didn’t we

B.did we

C.would he

D.wouldn’t he

8.The reporter said the news was not true, _________?

A.wasn’t it

B.didn’t he

C.did he

D.was it

9.They suggested that he should go to work at once, ________?

A.did they

B.didn’t they

C.should he

D.shouldn’t he

10.Your brother has lunch at home, _________-?

A.hasn’t he

B.doesn’t he

C.has he

D.does he

11.John has to get up early, ________? A.has he B.hasn’t he C.does he D.doesn’t he

12.She has got to get everything ready, _________?

A.hasn’t she

B.has she

C.doesn’t she

D.does she

13.She has never been to China, _________?A.has she B.hasn’t she C.doesn’t she D.does she

14.She had better tell you the news right now, _______?

A.had she

B.hadn’t she

C.did she

D.didn’t she

15.They would rather not have done that last week,________?

A.would they

B.wouldn’t they

C.have they

D.haven’t they

16.I’d rather stay here for a rest, ________?A.did I B.would I C.didn’t I D.wouldn’t I

17.You ought to do it again,_________?A.ought you B.oughtn’t you C.do you D.don’t you

18.You must do that again,_________?A.mustn’t you B.needn’t you C.do you D.don’t you

19.He must wait here, __________?A.mustn’t he B.doesn’t he C.shouldn’t he D.does he

20.He must be a good worker,________?A.mustn’t he B.needn’t he C.isn’t he D.doesn’t he

21.He must have been to China twice,_________?

A.hasn’t he

B.didn’t he

C.wasn’t he

D.mustn’t he

22.He must have been ill last week,__________?

A.hasn’t he

B.didn’t he

C.wasn’t he

D.mustn’t he

23.He must have known you during the war,__________?

A.hasn’t he

B.didn’t he

C.wasn’t he

D.mustn’t he