55楼kiki1018
(祝AMY身体健康!逢考必过!)
发表于 2010-1-20 11:34
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转自:新东方新概念2笔记
【Key structures】
Must, Have (got) to and Need
情态动词must(必须,不得不)的否定式 mustn't(不能、不准),must还可用于表示推测:
① 对现在和将来的推测:must +动词用原形
② 对正在发生的事情的推测:must be doing
③ 对过去的推测:must have done
④ 对过去正在发生的事情的推测:must have been doing
用must的一般疑问句可以用must/have to或needn’t来回答,而不用mustn’t:
Must I set off now?
Yes, you must / have to.
No, you needn’t.
mustn’t表示绝对禁止,在说话人看来,根本没选择余地:
You mustn’t use that bicycle. It’s broken.
“不必要”可用needn’t,don’t have to来表示:
needn’t = don’t have to
needn’t have done = didn’t have to
You needn’t / don’t have to work such long hours.
英语中的need有两种词性,一个是普通动词(需要),一种是情态动词。need的否定形式对应也有两种: needn't 不必(情态动词need的否定); don't need 不需要(普通动词need的否定)。
need I...?(情态) / do I need...? 实义动词
在实义动词后面再加一个实义动词, 就在后面加to do
Need I go out? = Do I need to go out? 我需要出去吗?
You needn’t have told me that. I know it is.
情态动词后面不能直接用名词做宾语,实义动词后面可以直接加名词, 故need 后面如是名词, 则这个need 为实义动词
例 : He__c__follow me .
a doesn’t need b needn’t to c didn’t need to d needs
情态动词need后接动词原形,但只用于否定和疑问句,肯定句用must,have to,ought to或should。
need用于疑问句时,问者往往希望得到否定的回答:
Need you leave so soon? 你有必要这么早就走吗?
用need的一般疑问句的肯定形式的回答可以用must/had to,否定形式的回答可以用needn’t:
Need I type this letter again?
Yes, you must. / No, you needn’t.
Need you have told him about my plans?
Yes, I had to. / No, I needn’t have.
表示必要时,must的语气比need要强:
I must go to the dentist this moring.
这种句型可用来表示说话人让对方选择或允许对方可以不做某事的主观意图。它的完成式和过去式分别为needn’t have,didn’t have to和didn’t need to:
I needn’t have gone to the office yesterday.
I didn’t have to / didn’t need to go to the office yesterday.
need doing sth. 需要被做(用主动表达被动含义)
① 这里need属于实义动词, 动词ing相当于名词来理解
② 有时态和人称变化,否定式为: don’t need doing
③ need doing 表达被动含义, 如: Your shoes need washing. 你的鞋子需(被)洗了
另外want doing也是用主动表示被动含义,它们的主语一定是物, 不是人
Your hair needs cuting.
need to be done---主语是人,也可以是物
The child need to be …
对比 mustn't和 needn't:
You musn’t read it bed. It’s bad for your eyes.
(be bad for… 对……有害)
Smoking is bad for your health. 抽烟有害你的健康
You mustn't make a noise. The children are asleep. 你不应吵闹, 孩子们都睡了.
You needn't drive so quickly. We have plenty of time.
你不必开得那么快, 我们有足够的时间.
=You don't have to(haven't got to) drive so quickly. We have plenty of time.
You mustn't smoke in a theatre. It is forbidden. 你不应该在剧场里抽烟, 这是不允许的.
You needn't come with us if you don't want to. 如果你不想去, 你不必和我们一道去.
=You don't have to (haven't got to) come with us if you don't want to.
昨天在做语法题的时候,涉及到这个问题.
今天回家重新讲解一下这些内容.
[ 本帖最后由 kiki1018 于 2010-1-20 11:35 编辑 ].