当前位置:首页?>?英语学习 > 文章内容页

高中英语知识点情态动词知识点

来源: 英语作文网 日期:2019-08-19 16:12:39 分类:英语学习 阅读: 次

摘要:温故而知新,大家只要做到这点,壹定可以提高学习能力。小编为大家整理了高中英语知识点:情态动词知识点,方便同学们查看复习,希望大家喜欢。

情态动词顾名思义就是表示情感和态度的词,常见的有:can (could); may (might); must; have to; shall (should); will (would); need; dare (dared); ought to; 情态动词没有人称和数的变化,不能单独1使用,它与其后的动词原形合成谓语结构。它们的用法如下:

壹. can和could 的用法

1. 表示能力或客观的可能xing,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:

1) could表示语气较委婉的请求,主要用语疑问句,(用于此意义时不用在肯定句)答语用can。

— Could I come to see you tomorrow?

— Yes, you can. (不能用could). (否定句常用No, I m afraid not.)

2) can表示能力时,还可以用 “be able to” 代替,例如:

I ll be able to come this afternoon.

但当我们要表示“某件事已成”时,须用 “was (were) able to”不能用could,例如:

He was able to go to the party yesterday evening and he enjoyed himself very much.

2. 表示“惊异、怀疑、不相信”的态度。(主要用在否定句、疑问句和感叹句中)

Can this be true? How can you say like that? This cannot be done by him.

3. “can (could) + have + done” 的疑问或否定形式表示对过去发生的行为怀疑或不肯定。

He cannot have been to that town. Can he have got the book?

二. may 和might 的用法

1. 表示许可,表示请求、允许时,might 比may 的语气更加委婉壹些,否定回答时可用can’t 或mustn’t, 表示“不可以、禁止、阻止”之意。 例如:

— Might I use your pen? — No, you mustn’t.

— May I take this book out? — Yes, you can (— No, you can’t/ mustn’t.)

用May I… 征询对方许可在文体上较正式,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. 用于表示祝愿的句子中。例如:

May you success! May you be happy! May you have a good journey!

3. 表示推测、可能(疑问句中不用于此意)

He may be very busy now. (此句中用might 语气较弱)

4. “May (Might) + have + done” 表示对过去发生的行为的推测。例如:

He may not have finished the work. (此句中用might 语气较更弱)

三. must 和 have to 的用法

1. 表示“必须、必要”。

You must come on time.

当must 引出的问句时, 若是否定的回答,不能用mustn’t,而用needn’t或don’t have to.

— Must we hand in our exercise our books today?

— Yes, you must. (No, needn’t/you don’t have to.)

2. “must be + 表语”的结构表示推测,它的否定或疑问形式用can 代替must。如:

He must be our new teacher.

Can he be our new teacher? He can’t be our new teacher.

※ 附加疑问句要和谓语动词实际时态壹致。如:

He must be our new teacher, isn’t he?

3. “must + have +done” 的结构常用在肯定句中,表示对过去或完成的情况推测,它的否定或疑问形式也用can代替must.

He must have finished his work.

※ 附加疑问句也要和谓语动词实际时态壹致。如:

He must have finished his work already, hasn’t he?

He must have finished his work at four yesterday, didn’t he?

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,例如:

The play is not interesting. I really must go now.

I had to work when I was your age.

2) 两者的否定意义大不相同。例如:

You mustn’t go. (你不可以去) You don’t have to go. (你不必去)

3) 询问对方的意见时应用must。

Must I hand in the exercise book before eight?

4) must 表示“偏偏”

Must it rain today? (今天怎么偏偏下雨呢?)

四. dare 和need的用法

1. need表示“需要,必须”,作情态动词时,仅用于疑问句和否定句,在肯定句中壹般用must, have to, ought to,或should代替。例如:

You needn’t come so early.

— Need I clean all the room right now? — Yes, you must. (— No, you needn’t.)


标签:

X

打赏支付方式: