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— No, you needn’t.不，不必啦.
2.need还可以用作行为动词，其变化和一般的动词相同。若主语为动作承受者时用动词主动形式表示被动意义或用不定式的被动形式。 We need to have a rest.我们需要休息一下。
The house needs repairing.=The house needs to be repaired.这栋房子需要修理。
(七)dare
dare作情态动词表示“敢于”，用于否定句、疑问句和条件句中。 She dare not go there.她不敢去那儿。
How dare he do such a thing? 他怎么敢做重要的事呢？
If he dare come, I will kick him out. 如果他胆敢来，我就把他踢出去。
1.惯用短语“I dare say”意为“我敢说、我想、或许”。 I dare say he is right.我敢说他是对的。
2.dare还可以用作行为动词，其变化与一般动词相同。 The girl didn't dare to go home.那个女孩不敢回家。 Do you dare to jump into the ocean? 跳进海洋里，你敢吗？ 【注意】在否定句中时，dare后的“to＋动词原形”可以省略to。 I don't dare (to) ask her. 我不敢问她。
(八) can ,may ,must皆可用来表示推测
1.在肯定句中都可以用来表示可能。在含义上“must”语气最肯定，“may”表示的是事实上的可能性。
2.在否定句中只能用“can和may”。所以“can’t”（不可能）语气比“may not”（可能不、也许不）更强。
3.在疑问句中只能用“can”，不能用“may和must”。 ①Peter ______come with us tonight, but he isn’t very sure yet. A. must
B. may
C. can
D. will
②Mary is in poor health. She can be ill at any times.
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Michael ______be a policeman, for he’s much too short. A. needn’t
B. can’t
C. should
D. may
③He may be very busy now. → Can he be very busy now? He must be very busy now. → Can he be very busy now?
④They can’t be cleaning the room now. 他们现在不可能在打扫房间。 注意：could ,might 表示推测时不表示时态，其推测的程度不如can ,may。
(九)情态动词+have done的用法
1.could+have done：过去本可以做而实际上未能做
You could have done better, but you didn’t try your best. 你本来能做得更好的，但你没有尽力。
2.cannot+have done：表示对过去行为的否定推测
He cannot have been to that town. 他不可能去过那个小镇。
3.can+主语+have done：（用于疑问句）表示对过去行为的怀疑或不肯定 Can he have got the book? 他可能得到那本书了吗？ 4.might(may)+ have done：对过去发生的行为不太肯定的推测 He may not have finished the work. 他可能没有完成工作。 If we had taken the other road, we might have arrived earlier. 如果我们走另一条路，我们可能更早地到达了。
5.must+have done：对过去发生的行为肯定的推测。其否定式为：cannot have done You must have seen the film. 你肯定看过那部电影。 You cannot have seen the film. 你不可能看过那部电影。 6.needn’t+have done：本来不必要做的而实际上又做了
You needn’t have watered the flowers, for it is going to rain.你本没必要浇花的，因为就要下雨了。
注意：didn’t need to(have to)do :没有必要做而实际上也没有做
I didn’t need to clean the windows. My sister did it 2 hours ago.我没必要擦窗户。我姐姐两小时前刚擦过。
7.should(ought to)+ have done：本来应该做而实际上又没有做。 其否定形式表示某种行为不该发生却发生了。
You should have started earlier, but you didn’t. 你应该早点开始的，但是你没有。
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She shouldn’t have taken away my measuring tape, for I wanted to use it.
他本不应该拿走我的字典的，因为我现在需要它。
（一）“if”虚拟条件句
主从句谓语动词的构成 情 况 与现在事实相反 与过去事实相反 与将来事实相反 从句谓语动词的构成 过去式（be用were） had+过去分词 过去式 should+动词原形 were+不定式 注意：从句中的should可用于各种人称，且不可以被would所代替。 If he were here, he would help us.如果他在这里，他会帮助我们的。 If I had been free at that time, I would have visited you.如果那时我有空的话，我就拜访你了。 If it should rain tomorrow, we would not go camping.如果明天下雨的话，我们就不去野营。 should/would/could/might+动词原形 主句谓语动词的构成 should/would/could/might+动词原形 should/would/could/might +have+过去分词 （二）省略“if”的虚拟条件句 将虚拟条件从句中的“were，had，should”放到主语之前，构成部分倒装 Should he come, tell him to ring me up.如果他来，告诉他让他给我打电话。 Were I you, I would not do it.如果我是你，我就不做。 Had I been free, I would have visited you.如果我有空的话，我就拜访你了。
（三）混合虚拟条件句
1.不同时间的虚拟，遵守相应的规则
If he had listened to me, he would not be in trouble now.
要是他听了我的话，现在就不会有麻烦了。（从句与过去事实相反，主句与现在事实相反）
If he had told me yesterday, I should know what to do now.
要是他昨天告诉我了，我就知道现在做什么了。（从句与过去事实相反，主句与现在事
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实相反）
If I were you, I would have gone to her birthday party.
如果我是你，我就去参加他的生日聚会了。（从句与现在事实相反，主句与过去事实相反）
2.虚拟与陈述的混合，遵守相应的规则
He could have passed the exam, but he wasn’t careful enough. 他本来能通过考试的，但他不够细心。
You should have come earlier. The bus left a moment ago. 你应该早一点来的，汽车刚走一会儿。
（四）含蓄虚拟条件句：即不用“if”而用其它形式给出虚拟条件 1.用“but for+名词”表示虚拟条件
—Did you make it at last? 你们最后成功了吗？
—Yes. But for your help, it would have caused a serious loss.成功了，要不是你的帮助，我们的损失就大了。
2.用“without+名词”表示虚拟条件
Without electricity, human life would be quite different today. 如果没有电的话，人类今天的生活就会大为不同。
3.用“动词不定式”表示虚拟条件
It would be only partly right to follow in this way. 如果这样做，仅仅对了一半。
4.用“现在分词”表示虚拟条件
Having known in time ,we might have prevented the accident. 要是及时得知的话，我们也许能阻止这场事故。
5.用“过去分词”表示虚拟条件
Given more attention, the tree could have grown better.如果多留心的话，这树本来可以长的更好。
6.用“副词otherwise”表示虚拟条件
I was too busy at that time. Otherwise, I would have called you.我当时太忙，否则我就给你打电话了。
7.用“连词but连接的句子”表示隐含的虚拟条件
He _________fatter but he eats too little.
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A. would become B. would have become C. must become D. must have become
【解析】答案为A。从后句“但是他吃得太少”来看，隐含着虚拟即：如果他吃得多点，就会胖些了。
（五）特殊句式虚拟结构
1.suggest, order, propose, request, require, demand, advise, insist+ 宾语从句(should )do
He suggested that we (should)not change our mind.他建议我们不要改变主意。 He insisted that he (should) go to work in the south.他坚持要到南方去工作。
注意：当suggest表示暗示，insist表示坚持观点，事实时，后接的宾语从句应当用真实语气。
His silence suggested that he agreed with my decision.他的沉默说明了他同意我的决定。 He insists that doing morning exercises does good to people’s health.他坚持认为做早操对人的身体有益。
2.It is suggested/advised/ordered/requested/required…+ that从句(should) do
It is suggested that more students should go to university.有人建议应该有更多的学生去上大学。
3.My advice/suggestion/request/requirement/order/proposal…+ is +表语从句(should)do
My advice is that you should practice speaking English as often as possible. 我的建议是有应该尽可能多地练习说英语。
4.His suggestion/advice/request/requirement…+ 同位语从句(should )do+ is..
The request that they should get more is reasonable.他们得到更多的要求是合理的。
5.It is natural/necessary/strange +that从句 (should) do表惊奇、怀疑、惋惜、不满、理应如此等。
It’s strange that he should have missed the train. 真奇怪，这样的一个人竟然是我们的朋友。（表竟然）
It is important that we should learn from others.重要的是我们理应向他人学习。（表理应如此）
It is a pity that he should not go with us.真遗憾，他不肯跟我们一起走。(表惋惜)
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