灵鹊做题网ENJOY 还有NO和NOT的区别,NOT一般放在情态动词后还是前,NO呢讲讲主谓宾定状补.列些情态动词副词是什么,TO
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ENJOY
还有NO和NOT的区别,NOT一般放在情态动词后还是前,NO呢
讲讲主谓宾定状补.列些情态动词
副词是什么,TO,FOR.OF.ON.IN的区别与用法.列个人称在各种形式的表.我知道问题很多.再列些重要短语
还有NO和NOT的区别,NOT一般放在情态动词后还是前,NO呢
讲讲主谓宾定状补.列些情态动词
副词是什么,TO,FOR.OF.ON.IN的区别与用法.列个人称在各种形式的表.我知道问题很多.再列些重要短语
享受做...
no和not的区别
no, not
这两个词都表示“否定”,但含义和使用场合不同.
no可作yes的相对语,给问句以否定回答.如：
—Are you from the States? 你是美国人吗?
—No, I’m from Canada. 不,我是加拿大人.
no 还可以表示not any/not a的意思,因此凡是和any或a 搭配的名词、动名词、形容词或副词,都可与no 搭配使用.如：
There were no (=not any) letters for you this morning. 今天上午没你的信.
It’s no difficult. =It’s not any difficult. 一点也不难.
no本身是个限定词,不可与另一个限定词,如a, any, that, the, all, both, ever, hi等连用,因此在出现上述限定词时,必须用not.如：
Not all of us saw it happen. 我们不是所有的人都看到这件事的发生.
在否定动词、副词、介词短语时,用not不用no.如：
I haven’t seen him quite recently. 最近我没有见过他.
I can make it Friday, but not Thursday. 定在星期五可以,但星期四不行.
由上可知,no和not any/not a都可放在名词前,但前者用于书面语较多,后者用于口语较多,而且前者没有后者的语气强.如：
I have no money left. 我没有余钱了.
I haven’t any money left. 我没有余钱了.
在动词为be的句子中,not (a) 却不如no.前者只表示“不是”这一事实,得带有一定的感情色彩.如：
I am no teacher. 我没有当老师的能力.
I am not a teacher. 我不是老师.
He is not good at tennis. 他不擅长于网球.
He is no good at tennis. 他网球打得很不好
主谓并定壮补 主干枝叶分清楚
语就是你要描述的对象(这不用多讲了吧~~)eg:I love you.中 "I"就是主语.
谓语就是由主语所发出的行为、动作等.一般都用动词作谓语,但不一定跟在主语后面哦!eg：I love you. 中"love"就是谓语.
宾语是动作、行为的对象,是动作的承受者.一般由名词或代词、不定式、名词性的短语充当.eg：I love you. "you"就是宾语. 而且在一个句子中不一定只有一个宾语喔! 就好像：I'll give you an apple. 中就有两个宾语“you”为间宾、“an apple” 为直宾.
顾名思义,对宾语进行补充说明的就是宾补了.eg：You make me happy. 中“me”是宾语,而“happy”是修饰“me”的,所以“happy”就是宾补啦!
同理可得： 对主语进行补充说明的就是主补啦~!
接着到定语；修饰名词或代词的成分就是定语；一般由形容词充当 eg：Echo is a naive girl. "naive"就是定语
状语：用来修饰动词、形容词、副词或整个句子的成分.主要由副词担任.此外,形容词、介词短语、名词词组、动词不定式短语也可以作状语.状语有分时间状语、地点状语、原因状语、条件状语、目的状语、方式状语、让步状语、情况状语 ；eg：I'll buy the ring in this morning. “in this morning”就是时间状语.
情态动词
定义:
情态动词是一种本身有一定的词义,但要与动词原形一起使用,给谓语动词增添情态色彩,表示说话人对有关行为或事物的态度和看法,认为其可能、应该或必要等.
情态动词后面加动词原形.
分类：
情态动词有四类：
①只做情态动词：must,can(could),may(might),ought to
②可做情态动词又可做实义动词：need,dare
③可做情态动词又可做助动词：shall(should),will(would)
④具有情态动词特征：have(had) to,used to
位置:
情态动词在句中放在谓语动词之前, 谓语动词前若有助动词,则在助动词之前,疑问句中, 情态动词则在主语之前.
I can see you. Come here.
我能看见你,过来吧.
He must have been away.
他一定走了.
What can I do for you?
我能帮你吗?
How dare you treat us like that!
你怎能那样对待我们!
特点:
情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 "not". 个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去,现在或将来.情态动词属非及物动词,故没有被动语态.
He could be here soon.
他很快就来.
We can't carry the heavy box.
我们搬不动那箱子.
I'm sorry I can't help you.
对不起,我帮不上你.
基本助动词与情态助动词最主要的区别之一是,基本助动词本身没有词义,而情态助动词则有自己的词义,能表示说话人对有关动作或状态的看法,或表示主观设想：
What have you been doing since? （构成完成进行体,本身无词义）
I am afraid I must be going. （一定要）
You may have read some account of the matter. （或许已经）
除此之外,情态助动词还有如下词法和句法特征：
1） 除ought和used以外,其他情态动词后面只能接不带to的不定式.如果我们把ought to和used to看做是固定词组的话,那么,所有情态动词无一例外地只能接不带to的不定式：
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2） 情态助动词在限定动词词组总是位居第一：
They need not have been punished so severely.
3） 情态助动词用于第三人称单数现在时的时候,没有词形变化,即其词尾无-s形式：
She dare not say what she thinks.
4） 情态动词没有非限定形式,即没有不定式和分词形式,也没有相应的动名词：
Still, she needn't have run away.
5） 情态助动词的“时”的形式并不是时间区别的主要标志.在不少场合,情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间：
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6） 情态助动词之间是相互排斥的,即在一个限定动词词组中只能出现一个情态助动词,但有时却可以与have和be基本助动词连用：
You should have washed the wound.
Well, you shouldn't be reading a novel.
用法
首先它是动词,而且不同于行为动词,行为动词表示的是可以通过行为来表达的动作（如写,读,跑）,而情态动词只是表达的一种想法（如能,也许,敢）.
用法是：情态动词+行为动词原形
例句：I can read this sentence in English.
我能用英语读这句话.
情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语.
We can be there on time tomorrow.我们明天能按时去那儿.
May I have your name? 我能知道你的名字吗?
Shall we begin now?我们现在就开始吗?
You must obey the school rules.你必须遵守校规.
情态动词数量不多,但用途广泛,主要有下列:
can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to) ,had better.
功能
助动词(auxiliary)主要有两类：基本助动词(primary auxiliary)和情态助动词(modal auxiliary).基本助动词有三个：do, have和be；情态助动词基本的有十四个：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to.had better 上述两类助动词的共同特征是,在协助主动词构成限定动词词组时,具有作用词的功能：
1） 构成否定式：
He didn't go and neither did she.
The meeting might not start until 5 o'clock.
2） 构成疑问式或附加疑问式：
Must you leave right now?
You have been learning French for 5 years, haven't you?
3） 构成修辞倒装：
Nowhere can he obtain any information about his sister.
Hardly had he arrived when she started complaining.
4） 代替限定动词词组：
A: Who can solve this crossword puzzle?
B: Tom can.
A: Shall I write to him?
B: Yes, do.
can和could的用法
1. 表示能力或客观可能性,还可以表示请求和允许.如：
Can you finish this work tonight?
Man cannot live without air.
— Can I go now? — Yes, you can.
注意：①could也可表示请求,语气委婉,主要用于疑问句,不可用于肯定句,答语应用can（即could不能用于现在时态的简略答语中）.如：
Could I come to see you tomorrow?
Yes, you can. （否定答语可用No, I'm afraid not.）
②can表示能力时,还可用be able to代替.如：
I'll not be able to come this afternoon.
2. 表示惊异、怀疑、不相信的态度.（主要用在否定句、疑问句或惊叹句中）
Can this be true?
How can you be so careless!
This cannot be done by him.
3. “can(could) + have + 过去分词”的疑问或否定形式表示对过去发生的行为怀疑或不肯定.如：
He cannot have been to that town.
Can he have got the book?
4. 用在疑问句及否定句中,表示惊讶,不相信等.
5. cannot```too\enough表示"无论怎样``````也不过分","越``````越好"
may和might的用法
1. 表示许可.
表示请求、允许时,might比may的语气更委婉一些,否定回答时(口语中常用) no , you can't . or , yes, please 用mustn't表示“不可以”、“禁止”、“阻止”之意(具有强烈禁止的意思)如：
You may drive the car.
— Might I use your pen? — No, you mustn't.
用May I ... 征询对方许可在文体上比较正式,在口气上比较客气.在日常口语中,用Can I ... 征询对方意见在现代口语中更为常见.
2. 用于祈使句中表示祝愿.如：
May you succeed!
3. 表示推测、可能（疑问句不能用于此意）.
He may be very busy now.
4. “may(might) + have + 过去分词”表示对过去发生的行为的推测.如：
He may not have finished the work.
must和have to的用法
1. 表示必须、必要.（must表示主观多一些而have to则表示客观多一些）如：
You must come in time.
回答must引出的问句时,如果是否定的回答,不能用mustn't,而要用needn't或don't have to.
— Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to.)
2. “must be + 表语”的结构表示推测,它的否定或疑问式用can代替must.
This must be your pen.
3. “must + have + 过去分词”的结构常用在肯定句中,表示对过去发生的行为的推测.它的否定或疑问式用can代替must.
He must have been to Shanghai.
4. have to的含义与must相似,两者往往可以互换使用,但have to有各种形式,随have的变化而定.must与have to有下列几点不同：
① must表示的是说话人的主观看法,而have to则往往强调客观需要.如：
The play is not interesting. I really must go now.
I had to work when I was your age.
② must一般只表现在,have则有更多的时态形式.
③ 二者的否定意义不大相同.如：
You mustn't go. 你可不要去.
You don't have to go. 你不必去.
④ 询问对方的意愿时应用must.如：
Must I clean all the room?
注意：have to也可拼做have got to.
dare和need的用法
1. need表示“需要”或“必须”,作情态动词时,仅用于否定句或疑问句中,在肯定句中一般用must, have to, ought to,或should代替.如：
You needn’t come so early.
— Need I finish the work today?
— Yes, you must.
注意：needn't + 不定式的完成式“表示本来不必做某事而实际上做了某事”.如：
You needn't have waited for me.
2. Dare作情态动词时,主要用于疑问句、否定句和条件从句中,一般不用在肯定句中.如：
How dare you say I'm unfair.
He daren't speak English before such a crowd, dare he?
3. Dare和need常用作实义动词,有时态、人称和数的变化,所不同的是,作实义动词时,在肯定句中,dare后面通常接带to的不定式,在否定和疑问句中,dare后面可接带to或不带to的不定式.如：
I dare to swim across this river.
He does not dare (to) answer.
Don't you dare (to) touch it!
I wondered he dare (to) say that.
He needs to finish it this evening.
shall和should的用法
一.Shall的用法：
1. Shall用于第一人称,表示征求对方的意愿.如：
What shall we do this evening?
2. Shall用于第一、第三人称疑问句中,表示说话人征求对方的意见或向对方请示.如：
Shall we begin our lesson?
When shall he be able to leave the hospital?
3. Shall用于第二、第三人称,表示说话人给对方命令、警告、允诺或威胁.如：
You shall fail if you don't work harder. （警告）
He shall have the book when I finish reading. （允诺）
He shall be punished. （威胁）
二.Should的用法：
1. Should表示劝告、建议、命令,其同义词是ought to；在疑问句中,通常用should代替ought to.如：
You should go to class right away.
Should I open the window?
Should的含义较多,用法较活,现介绍三种其特殊用法.请看下面的句子：
① I should think it would be better to try it again. 我倒是认为最好再试一试.
② You are mistaken, I should say. 依我看,你是搞错了.
③ I should advise you not to do that. 我倒是劝你别这样做.
④ This is something I should have liked to ask you. 这是我本来想问你的.
从以上例句可以看出：情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气.
Should还可以用在if引导的条件从句,表示一件事听起来可能性很小,但也不是完全没有可能.相当于“万一”的意思.从句谓语由should加动词原形构成,主句谓语却不一定用虚拟语气.如：
⑤ Ask her to ring me up if you should see her. 你万一见到她,请让她给我打个电话.
⑥ If you should change your mind, please let us know. 万一你改变主意,请通知我们.
⑦ Should I (If I should) be free tomorrow I will come. 万一我明天有时间,我就来.
此外,Why(or How) + should结构表示说话人对某事不能理解,感到意外、惊异等意思.意为“竟会”.如：
⑧ Why should you be so late today? 你几天怎么来得这么晚?
⑨ — Where is Betty living? — 贝蒂住在哪里?
— How should I know? — 我怎么会知道呢?
⑩ I don't know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的.
2. “should + have + 过去分词”结构一般表示义务,表示应该做到而实际上没有做到,并包含一种埋怨、责备的口气.如： She should have finished it.
I should have helped her, but I never could.
You should have started earlier.
will和would的用法
1. 表示请求、建议等,would比will委婉客气.如：
Would you pass me the book?
2. 表示意志、愿望和决心.如：
I will never do that again.
They asked if we would do that again.
The door won't open
3. 用“will be”和“will(would) + have + 过去分词”的结构表示推测,主要用于第二、三人称.前者表示对目前情况的推测,后者表示对已经完成的动作或事态的推测.如：
This will be the book you want.
He will have arrived by now.
The guests would have arrived by that time.
I thought you would have finished this by now.
4. Would可表示过去反复发生的动作或某种倾向.Would表过去习惯时比used to正式,并没有“现已无此习惯”的含义.如：
The wound would not heal.
During the vacation he would visit me every week.
5. 表料想或猜想.如：
It would be about ten when he left home.
What would she be doing there?
I thought he would have told you all about it.
ought to的用法
1. Ought to表示应该.如：
You ought to take care of him.
2. 表示推测.注意与must表示推测时的区别：
He must be at home by now. （断定他已到家）
He ought to be home by now. （不十分肯定）
This is where the oil must be. （比较直率）
This is where the oil ought to be. （比较含蓄）
3. “ought to + have + 过去分词”表示过去应做某事而实际未做.如：
You ought to have asked him (but you didn't).
这时,ought to和should可以互相换用.
注意：在美国英语中,ought to用于否定句和疑问句时,to可以省略.如：
Ought you smoke so much?
You oughtn't smoke so much.
ought和should的区别：
1.ought语气略强.
2.should较常用.
3.ought在美国英语中用的很少,而should却相当常用.
4.ought属正式用语.
used to,had better,would rather的用法
1. Used to表示过去的习惯动作或状态,现在已不存在,在间接引语中,其形式可不变.如：
He told us he used to play football when he was young.
在疑问句、否定句、否定疑问句或强调句中,可有两种形式：
疑问句
Did you use to go to the same school as your brother?
Used you to go to the same school as your brother?
否定句
I usedn't to go there.
I didn't use to go there.
Usedn't 亦可拼作usen't,但发音皆为['ju:snt].
否定疑问句
Usen't you to be interested in the theatre?
Didn't you use to be interested in the theatre?
强调句
I certainly used to smoke, but it was a long time ago.
I certainly did use to smoke, but it was a long time ago.
其反意疑问句或简略回答中,也有两种形式：
She used to be very fat, didn't she? （口语+常用）/ use(d)n't she? （正式+过时）
Did you use to play chess? Yes, I did.
Used you to get up early in the morning? Yes, I did. (Yes, I used to.)
2. Had better意为“最好”,后接不带to的不定式.如：
— We had better go now.
— Yes, we had (we'd better / we had better).
Hadn't we better stop now? (Had we better not stop now?)
I think I'd better be going. （用于进行时态,表“最好立即”）
You had better have done that. （用于完成时态,表未完成动作）
注：①had best与had better同意,但较少用.②You had better … 用于同辈或小辈,对长辈不可用.
3. Would rather意为“宁愿”,表选择,后接不带to的不定式.如：
I'd rather not say anything.
Would you rather work on a farm?
— Wouldn't you rather stay here?
— No, I would not. I'd rather go there.
由于would rather表选择,因而后可接than.如：
I would rather work on a farm than in a factory.
I would rather watch TV than go to see the film.
I would rather lose a dozen cherry trees than that you should tell me one lie.
I'd rather you didn't talk about this to anyone. （句中的'd rather不是情态动词,would在此是表愿望的实义动词）
can (could), may (might), 用法:
can (could) 表示说话人能,可以,同意,准许,以及客观条件许可,could 为 can 的过去式.
Can you pass me the books?
你能给我递一下书吗 ?
Could you help me, please?
请问,你能帮助我吗?
What can you do?
你能干点什么呢?
Can you be sure?
你有把握吗?
can 和could 只能用于现在式和过去式两种时态,将来时态用 be able to 来表示.
He could help us at all.
他完全可以帮助我们.
With the teacher's help,I shall be able to speak English correctly.
由于老师的帮助,我将能准确地讲英语.
may (might) 可以, 表示说话人同意,许可或请求对方许可.
You may take the book home.
你可以把书带回家去.
May I come in?
我可以进来吗?
May I use your dictionary?
我可以用你的词典吗?
You may put on more clothes.
你可以多穿点衣服.
He said he might lend us some money.
他说他可以借给我们一些钱.
may 否定式为 may not, 缩写形式是 mayn't.
might 是may 的过去式, 有两种用法, 一种表示过去式,一种表示虚拟语气, 使语气更加委婉, 客气或对可能性的怀疑.
He told me he might be here on time.
他说他能按时间来.
Might I borrow some money now.
我可以借点钱吗?
He might be alive.
他可能还活着.
must, need, ought to, dare (dared)用法
Must 必须,应该,一定,准是, 表示说话人认为有必要做某事, 命令, 要求别人做某事以及对事物的推测.
must 用来指一般现在时和一般将来时, 过去式可用 have to 的过去式代替.
I must finish my work today. 我今天必须完成我的工作.
You mustn't work all the time. 你不能老是工作.
Must I return the book tomorrow? 我必须明天还书吗?
After such a long walk, you must be tired. 走了这么长的路,你一定困了.
He must be the man I am looking for. 他一定是我要找的人.
He had to go because of somebody's calling him that day. 那天他要走是因为有人叫他.
must + have + 过去分词,表示现在对过去事物的推测.
He must have told my parents about it.
他一定把这件事情告诉我父母亲了.
He must have received my letter now.
他现在一定收到我的信了.
It's six o'clock already, we must have been late again.
已经六点钟了,我们一定又迟到了.
must 和 have to 的区别: must 表示说话人的主观思想, have to 表示客观需要.
You must do it now.
你必需现在就干.(说话人认为必须现在干)
I have to go now.
我得走了.(客观条件必须现在走)
need 需要 多用在否定式或疑问句中.
Need I attend the meeting tomorrow?
我需要明天参加会议吗?
You need not hand in the paper this week.
这一周你不必交论文.
need 是一个情态动词, 他的用法完全和其他情态动词一样, 但 need 还可当作实义动词使用, 这时 need 就象其他动词一样,有第三人称,单复数, 后面加带 to 的动词等特性.
I need a bike to go to school.
我上学需要一辆自行车.
Do you need a dictionary?
你需要词典吗?
She needs a necklace.
她需要一条项链.
needn't + have + 过去分词 表示过去做了没必要做的事情.
You needn't have taken it seriously.
这件事情你不必太认真.
dare 敢 多用在否定或疑问句中.
The little girl dare not speak in public.
小女孩不敢在公众面前说话.
Dare you catch the little cat?
你敢抓小猫吗?
dare 除用作情态动词外,更多的是当实义动词使用, 用法同实义动词一样,要考虑人称,单复数,时态等.
Do you dare to walk in the dark?
你敢黑夜走路吗?
He doesn't dare to tell the teacher what happened that day.
他不敢告诉老师那天发生的事.
no和not的区别
no, not
这两个词都表示“否定”,但含义和使用场合不同.
no可作yes的相对语,给问句以否定回答.如：
—Are you from the States? 你是美国人吗?
—No, I’m from Canada. 不,我是加拿大人.
no 还可以表示not any/not a的意思,因此凡是和any或a 搭配的名词、动名词、形容词或副词,都可与no 搭配使用.如：
There were no (=not any) letters for you this morning. 今天上午没你的信.
It’s no difficult. =It’s not any difficult. 一点也不难.
no本身是个限定词,不可与另一个限定词,如a, any, that, the, all, both, ever, hi等连用,因此在出现上述限定词时,必须用not.如：
Not all of us saw it happen. 我们不是所有的人都看到这件事的发生.
在否定动词、副词、介词短语时,用not不用no.如：
I haven’t seen him quite recently. 最近我没有见过他.
I can make it Friday, but not Thursday. 定在星期五可以,但星期四不行.
由上可知,no和not any/not a都可放在名词前,但前者用于书面语较多,后者用于口语较多,而且前者没有后者的语气强.如：
I have no money left. 我没有余钱了.
I haven’t any money left. 我没有余钱了.
在动词为be的句子中,not (a) 却不如no.前者只表示“不是”这一事实,得带有一定的感情色彩.如：
I am no teacher. 我没有当老师的能力.
I am not a teacher. 我不是老师.
He is not good at tennis. 他不擅长于网球.
He is no good at tennis. 他网球打得很不好
主谓并定壮补 主干枝叶分清楚
语就是你要描述的对象(这不用多讲了吧~~)eg:I love you.中 "I"就是主语.
谓语就是由主语所发出的行为、动作等.一般都用动词作谓语,但不一定跟在主语后面哦!eg：I love you. 中"love"就是谓语.
宾语是动作、行为的对象,是动作的承受者.一般由名词或代词、不定式、名词性的短语充当.eg：I love you. "you"就是宾语. 而且在一个句子中不一定只有一个宾语喔! 就好像：I'll give you an apple. 中就有两个宾语“you”为间宾、“an apple” 为直宾.
顾名思义,对宾语进行补充说明的就是宾补了.eg：You make me happy. 中“me”是宾语,而“happy”是修饰“me”的,所以“happy”就是宾补啦!
同理可得： 对主语进行补充说明的就是主补啦~!
接着到定语；修饰名词或代词的成分就是定语；一般由形容词充当 eg：Echo is a naive girl. "naive"就是定语
状语：用来修饰动词、形容词、副词或整个句子的成分.主要由副词担任.此外,形容词、介词短语、名词词组、动词不定式短语也可以作状语.状语有分时间状语、地点状语、原因状语、条件状语、目的状语、方式状语、让步状语、情况状语 ；eg：I'll buy the ring in this morning. “in this morning”就是时间状语.
情态动词
定义:
情态动词是一种本身有一定的词义,但要与动词原形一起使用,给谓语动词增添情态色彩,表示说话人对有关行为或事物的态度和看法,认为其可能、应该或必要等.
情态动词后面加动词原形.
分类：
情态动词有四类：
①只做情态动词：must,can(could),may(might),ought to
②可做情态动词又可做实义动词：need,dare
③可做情态动词又可做助动词：shall(should),will(would)
④具有情态动词特征：have(had) to,used to
位置:
情态动词在句中放在谓语动词之前, 谓语动词前若有助动词,则在助动词之前,疑问句中, 情态动词则在主语之前.
I can see you. Come here.
我能看见你,过来吧.
He must have been away.
他一定走了.
What can I do for you?
我能帮你吗?
How dare you treat us like that!
你怎能那样对待我们!
特点:
情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 "not". 个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去,现在或将来.情态动词属非及物动词,故没有被动语态.
He could be here soon.
他很快就来.
We can't carry the heavy box.
我们搬不动那箱子.
I'm sorry I can't help you.
对不起,我帮不上你.
基本助动词与情态助动词最主要的区别之一是,基本助动词本身没有词义,而情态助动词则有自己的词义,能表示说话人对有关动作或状态的看法,或表示主观设想：
What have you been doing since? （构成完成进行体,本身无词义）
I am afraid I must be going. （一定要）
You may have read some account of the matter. （或许已经）
除此之外,情态助动词还有如下词法和句法特征：
1） 除ought和used以外,其他情态动词后面只能接不带to的不定式.如果我们把ought to和used to看做是固定词组的话,那么,所有情态动词无一例外地只能接不带to的不定式：
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2） 情态助动词在限定动词词组总是位居第一：
They need not have been punished so severely.
3） 情态助动词用于第三人称单数现在时的时候,没有词形变化,即其词尾无-s形式：
She dare not say what she thinks.
4） 情态动词没有非限定形式,即没有不定式和分词形式,也没有相应的动名词：
Still, she needn't have run away.
5） 情态助动词的“时”的形式并不是时间区别的主要标志.在不少场合,情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间：
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6） 情态助动词之间是相互排斥的,即在一个限定动词词组中只能出现一个情态助动词,但有时却可以与have和be基本助动词连用：
You should have washed the wound.
Well, you shouldn't be reading a novel.
用法
首先它是动词,而且不同于行为动词,行为动词表示的是可以通过行为来表达的动作（如写,读,跑）,而情态动词只是表达的一种想法（如能,也许,敢）.
用法是：情态动词+行为动词原形
例句：I can read this sentence in English.
我能用英语读这句话.
情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语.
We can be there on time tomorrow.我们明天能按时去那儿.
May I have your name? 我能知道你的名字吗?
Shall we begin now?我们现在就开始吗?
You must obey the school rules.你必须遵守校规.
情态动词数量不多,但用途广泛,主要有下列:
can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to) ,had better.
功能
助动词(auxiliary)主要有两类：基本助动词(primary auxiliary)和情态助动词(modal auxiliary).基本助动词有三个：do, have和be；情态助动词基本的有十四个：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to.had better 上述两类助动词的共同特征是,在协助主动词构成限定动词词组时,具有作用词的功能：
1） 构成否定式：
He didn't go and neither did she.
The meeting might not start until 5 o'clock.
2） 构成疑问式或附加疑问式：
Must you leave right now?
You have been learning French for 5 years, haven't you?
3） 构成修辞倒装：
Nowhere can he obtain any information about his sister.
Hardly had he arrived when she started complaining.
4） 代替限定动词词组：
A: Who can solve this crossword puzzle?
B: Tom can.
A: Shall I write to him?
B: Yes, do.
can和could的用法
1. 表示能力或客观可能性,还可以表示请求和允许.如：
Can you finish this work tonight?
Man cannot live without air.
— Can I go now? — Yes, you can.
注意：①could也可表示请求,语气委婉,主要用于疑问句,不可用于肯定句,答语应用can（即could不能用于现在时态的简略答语中）.如：
Could I come to see you tomorrow?
Yes, you can. （否定答语可用No, I'm afraid not.）
②can表示能力时,还可用be able to代替.如：
I'll not be able to come this afternoon.
2. 表示惊异、怀疑、不相信的态度.（主要用在否定句、疑问句或惊叹句中）
Can this be true?
How can you be so careless!
This cannot be done by him.
3. “can(could) + have + 过去分词”的疑问或否定形式表示对过去发生的行为怀疑或不肯定.如：
He cannot have been to that town.
Can he have got the book?
4. 用在疑问句及否定句中,表示惊讶,不相信等.
5. cannot```too\enough表示"无论怎样``````也不过分","越``````越好"
may和might的用法
1. 表示许可.
表示请求、允许时,might比may的语气更委婉一些,否定回答时(口语中常用) no , you can't . or , yes, please 用mustn't表示“不可以”、“禁止”、“阻止”之意(具有强烈禁止的意思)如：
You may drive the car.
— Might I use your pen? — No, you mustn't.
用May I ... 征询对方许可在文体上比较正式,在口气上比较客气.在日常口语中,用Can I ... 征询对方意见在现代口语中更为常见.
2. 用于祈使句中表示祝愿.如：
May you succeed!
3. 表示推测、可能（疑问句不能用于此意）.
He may be very busy now.
4. “may(might) + have + 过去分词”表示对过去发生的行为的推测.如：
He may not have finished the work.
must和have to的用法
1. 表示必须、必要.（must表示主观多一些而have to则表示客观多一些）如：
You must come in time.
回答must引出的问句时,如果是否定的回答,不能用mustn't,而要用needn't或don't have to.
— Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to.)
2. “must be + 表语”的结构表示推测,它的否定或疑问式用can代替must.
This must be your pen.
3. “must + have + 过去分词”的结构常用在肯定句中,表示对过去发生的行为的推测.它的否定或疑问式用can代替must.
He must have been to Shanghai.
4. have to的含义与must相似,两者往往可以互换使用,但have to有各种形式,随have的变化而定.must与have to有下列几点不同：
① must表示的是说话人的主观看法,而have to则往往强调客观需要.如：
The play is not interesting. I really must go now.
I had to work when I was your age.
② must一般只表现在,have则有更多的时态形式.
③ 二者的否定意义不大相同.如：
You mustn't go. 你可不要去.
You don't have to go. 你不必去.
④ 询问对方的意愿时应用must.如：
Must I clean all the room?
注意：have to也可拼做have got to.
dare和need的用法
1. need表示“需要”或“必须”,作情态动词时,仅用于否定句或疑问句中,在肯定句中一般用must, have to, ought to,或should代替.如：
You needn’t come so early.
— Need I finish the work today?
— Yes, you must.
注意：needn't + 不定式的完成式“表示本来不必做某事而实际上做了某事”.如：
You needn't have waited for me.
2. Dare作情态动词时,主要用于疑问句、否定句和条件从句中,一般不用在肯定句中.如：
How dare you say I'm unfair.
He daren't speak English before such a crowd, dare he?
3. Dare和need常用作实义动词,有时态、人称和数的变化,所不同的是,作实义动词时,在肯定句中,dare后面通常接带to的不定式,在否定和疑问句中,dare后面可接带to或不带to的不定式.如：
I dare to swim across this river.
He does not dare (to) answer.
Don't you dare (to) touch it!
I wondered he dare (to) say that.
He needs to finish it this evening.
shall和should的用法
一.Shall的用法：
1. Shall用于第一人称,表示征求对方的意愿.如：
What shall we do this evening?
2. Shall用于第一、第三人称疑问句中,表示说话人征求对方的意见或向对方请示.如：
Shall we begin our lesson?
When shall he be able to leave the hospital?
3. Shall用于第二、第三人称,表示说话人给对方命令、警告、允诺或威胁.如：
You shall fail if you don't work harder. （警告）
He shall have the book when I finish reading. （允诺）
He shall be punished. （威胁）
二.Should的用法：
1. Should表示劝告、建议、命令,其同义词是ought to；在疑问句中,通常用should代替ought to.如：
You should go to class right away.
Should I open the window?
Should的含义较多,用法较活,现介绍三种其特殊用法.请看下面的句子：
① I should think it would be better to try it again. 我倒是认为最好再试一试.
② You are mistaken, I should say. 依我看,你是搞错了.
③ I should advise you not to do that. 我倒是劝你别这样做.
④ This is something I should have liked to ask you. 这是我本来想问你的.
从以上例句可以看出：情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气.
Should还可以用在if引导的条件从句,表示一件事听起来可能性很小,但也不是完全没有可能.相当于“万一”的意思.从句谓语由should加动词原形构成,主句谓语却不一定用虚拟语气.如：
⑤ Ask her to ring me up if you should see her. 你万一见到她,请让她给我打个电话.
⑥ If you should change your mind, please let us know. 万一你改变主意,请通知我们.
⑦ Should I (If I should) be free tomorrow I will come. 万一我明天有时间,我就来.
此外,Why(or How) + should结构表示说话人对某事不能理解,感到意外、惊异等意思.意为“竟会”.如：
⑧ Why should you be so late today? 你几天怎么来得这么晚?
⑨ — Where is Betty living? — 贝蒂住在哪里?
— How should I know? — 我怎么会知道呢?
⑩ I don't know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的.
2. “should + have + 过去分词”结构一般表示义务,表示应该做到而实际上没有做到,并包含一种埋怨、责备的口气.如： She should have finished it.
I should have helped her, but I never could.
You should have started earlier.
will和would的用法
1. 表示请求、建议等,would比will委婉客气.如：
Would you pass me the book?
2. 表示意志、愿望和决心.如：
I will never do that again.
They asked if we would do that again.
The door won't open
3. 用“will be”和“will(would) + have + 过去分词”的结构表示推测,主要用于第二、三人称.前者表示对目前情况的推测,后者表示对已经完成的动作或事态的推测.如：
This will be the book you want.
He will have arrived by now.
The guests would have arrived by that time.
I thought you would have finished this by now.
4. Would可表示过去反复发生的动作或某种倾向.Would表过去习惯时比used to正式,并没有“现已无此习惯”的含义.如：
The wound would not heal.
During the vacation he would visit me every week.
5. 表料想或猜想.如：
It would be about ten when he left home.
What would she be doing there?
I thought he would have told you all about it.
ought to的用法
1. Ought to表示应该.如：
You ought to take care of him.
2. 表示推测.注意与must表示推测时的区别：
He must be at home by now. （断定他已到家）
He ought to be home by now. （不十分肯定）
This is where the oil must be. （比较直率）
This is where the oil ought to be. （比较含蓄）
3. “ought to + have + 过去分词”表示过去应做某事而实际未做.如：
You ought to have asked him (but you didn't).
这时,ought to和should可以互相换用.
注意：在美国英语中,ought to用于否定句和疑问句时,to可以省略.如：
Ought you smoke so much?
You oughtn't smoke so much.
ought和should的区别：
1.ought语气略强.
2.should较常用.
3.ought在美国英语中用的很少,而should却相当常用.
4.ought属正式用语.
used to,had better,would rather的用法
1. Used to表示过去的习惯动作或状态,现在已不存在,在间接引语中,其形式可不变.如：
He told us he used to play football when he was young.
在疑问句、否定句、否定疑问句或强调句中,可有两种形式：
疑问句
Did you use to go to the same school as your brother?
Used you to go to the same school as your brother?
否定句
I usedn't to go there.
I didn't use to go there.
Usedn't 亦可拼作usen't,但发音皆为['ju:snt].
否定疑问句
Usen't you to be interested in the theatre?
Didn't you use to be interested in the theatre?
强调句
I certainly used to smoke, but it was a long time ago.
I certainly did use to smoke, but it was a long time ago.
其反意疑问句或简略回答中,也有两种形式：
She used to be very fat, didn't she? （口语+常用）/ use(d)n't she? （正式+过时）
Did you use to play chess? Yes, I did.
Used you to get up early in the morning? Yes, I did. (Yes, I used to.)
2. Had better意为“最好”,后接不带to的不定式.如：
— We had better go now.
— Yes, we had (we'd better / we had better).
Hadn't we better stop now? (Had we better not stop now?)
I think I'd better be going. （用于进行时态,表“最好立即”）
You had better have done that. （用于完成时态,表未完成动作）
注：①had best与had better同意,但较少用.②You had better … 用于同辈或小辈,对长辈不可用.
3. Would rather意为“宁愿”,表选择,后接不带to的不定式.如：
I'd rather not say anything.
Would you rather work on a farm?
— Wouldn't you rather stay here?
— No, I would not. I'd rather go there.
由于would rather表选择,因而后可接than.如：
I would rather work on a farm than in a factory.
I would rather watch TV than go to see the film.
I would rather lose a dozen cherry trees than that you should tell me one lie.
I'd rather you didn't talk about this to anyone. （句中的'd rather不是情态动词,would在此是表愿望的实义动词）
can (could), may (might), 用法:
can (could) 表示说话人能,可以,同意,准许,以及客观条件许可,could 为 can 的过去式.
Can you pass me the books?
你能给我递一下书吗 ?
Could you help me, please?
请问,你能帮助我吗?
What can you do?
你能干点什么呢?
Can you be sure?
你有把握吗?
can 和could 只能用于现在式和过去式两种时态,将来时态用 be able to 来表示.
He could help us at all.
他完全可以帮助我们.
With the teacher's help,I shall be able to speak English correctly.
由于老师的帮助,我将能准确地讲英语.
may (might) 可以, 表示说话人同意,许可或请求对方许可.
You may take the book home.
你可以把书带回家去.
May I come in?
我可以进来吗?
May I use your dictionary?
我可以用你的词典吗?
You may put on more clothes.
你可以多穿点衣服.
He said he might lend us some money.
他说他可以借给我们一些钱.
may 否定式为 may not, 缩写形式是 mayn't.
might 是may 的过去式, 有两种用法, 一种表示过去式,一种表示虚拟语气, 使语气更加委婉, 客气或对可能性的怀疑.
He told me he might be here on time.
他说他能按时间来.
Might I borrow some money now.
我可以借点钱吗?
He might be alive.
他可能还活着.
must, need, ought to, dare (dared)用法
Must 必须,应该,一定,准是, 表示说话人认为有必要做某事, 命令, 要求别人做某事以及对事物的推测.
must 用来指一般现在时和一般将来时, 过去式可用 have to 的过去式代替.
I must finish my work today. 我今天必须完成我的工作.
You mustn't work all the time. 你不能老是工作.
Must I return the book tomorrow? 我必须明天还书吗?
After such a long walk, you must be tired. 走了这么长的路,你一定困了.
He must be the man I am looking for. 他一定是我要找的人.
He had to go because of somebody's calling him that day. 那天他要走是因为有人叫他.
must + have + 过去分词,表示现在对过去事物的推测.
He must have told my parents about it.
他一定把这件事情告诉我父母亲了.
He must have received my letter now.
他现在一定收到我的信了.
It's six o'clock already, we must have been late again.
已经六点钟了,我们一定又迟到了.
must 和 have to 的区别: must 表示说话人的主观思想, have to 表示客观需要.
You must do it now.
你必需现在就干.(说话人认为必须现在干)
I have to go now.
我得走了.(客观条件必须现在走)
need 需要 多用在否定式或疑问句中.
Need I attend the meeting tomorrow?
我需要明天参加会议吗?
You need not hand in the paper this week.
这一周你不必交论文.
need 是一个情态动词, 他的用法完全和其他情态动词一样, 但 need 还可当作实义动词使用, 这时 need 就象其他动词一样,有第三人称,单复数, 后面加带 to 的动词等特性.
I need a bike to go to school.
我上学需要一辆自行车.
Do you need a dictionary?
你需要词典吗?
She needs a necklace.
她需要一条项链.
needn't + have + 过去分词 表示过去做了没必要做的事情.
You needn't have taken it seriously.
这件事情你不必太认真.
dare 敢 多用在否定或疑问句中.
The little girl dare not speak in public.
小女孩不敢在公众面前说话.
Dare you catch the little cat?
你敢抓小猫吗?
dare 除用作情态动词外,更多的是当实义动词使用, 用法同实义动词一样,要考虑人称,单复数,时态等.
Do you dare to walk in the dark?
你敢黑夜走路吗?
He doesn't dare to tell the teacher what happened that day.
他不敢告诉老师那天发生的事.