Need 和 dare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.
Have to和must的用法
1. 表示必须、必要。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?
（二）语法练习
I. Choices
1. You _______ angry with her, for she is very young.
A. need not to be B. don’t need to
C. need not be D. need not
2. You look pale. You _______ ill.
A. can be B. must be C. should be D. has to be
3. You _________ read that book if you don’t want to.
A haven’t B. can’t C. mustn’t D. needn’t
4. I want to go to the doctor, but you ________with me.
A. need not to go B. do not need go
C. need not go D. need go not
5. You ________ yourself about money.
A. need not worry B. have worry
C. are not being worried D. need not be worried
6. There was plenty of time. She ___________.
A. mustn’t have hurried B. couldn’t have hurried
上一页 [1] [2] [3] [4] [5] [6] 下一页
高一英语Food for thought教案1