第1个回答 2013-04-16
1. 表示“必须”、“一定要”
(1) 可用于肯定句、否定句或疑问句;用于否定句时,mustn't 的意思是“一定不要”、“不能”,而不是“不必”:You must finish it today. 你一定要在今天完成它。You must see the doctor. 你一定要看医生。Must you go so soon? 你一定得这么早就走吗?We mustn't think only of ourselves. 我们可不能只考虑自己。
(2) 主要表示现在或将来,但有时(如在间接引语中)也可表过去(=had to):She asked if she must (had to) leave. 她问她是否一定要离开。
(3) 对于must 开头一般疑问句,若要作否定回答,可用needn't,不用mustn't:"Must I come over tonight?" "No, you needn't." “我今晚必须过来吗?”“不必。”
(4) 其后可接被动结构或进行形式:Something must be done to stop it. 必须采取措施来阻止它。I think I must be going. I think I must be going. 我想我得走了。2. 表示推测。意为“准是”、“一定是”(1) 通常只用于肯定句,在否定句或疑问句用 can 代之:It must be true. 那一定是真的。It must be true. 比较:Can it be true? 那可能是真的吗? / It can't be true. 那不可能是真的。(2) 后接动词原形,表示对现在情况的推测: He must be wrong. 他一定错了。The man must have a lot of money. 这个人一定有不少钱。注:must 表示对现在情况的推测后接动词原形时,该动词通常为状态动词(如 be, have, know 等),若为动作动词,通常要转换其它说法。“他一定会赢”,通常不说He must win,可说He is sure to win。(He must win的意思是“他必须要赢”) (3) 其后可接进行式或完成进行式,用以谈论一个正在进行的动作:He must be writing a letter to his girl friend. 他一定在给他女朋友写信。Someone must have been smoking here.一定有人一直在这里抽烟。(4) 后接不定式的完成式,用来谈论已发生的情况:He must have arrived already.他一定已经到了。I didn't hear the phone. I must have been asleep. 我没有听到电话铃,我一定是睡着了。3. 表示“应当”。相当于should, ought to的意思You must say hello to her.你应当跟她打个招呼。We must go and have a weekend there.我们应当到那里度周末。4. 表示“偏偏”有时表示不巧,有时表示固执,通常都是指令人不快的事:Must you make so much noise? 你就非得弄出这么大的声音吗?Why must you always interrupt me? 你为什么硬是老要打断我?We were ready to leave, but the baby must catch cold. 我们刚准备好要走, 可孩子偏偏得了感冒。Just when I was busy, the neighbor must come and chatter. 正当我忙碌的时候,邻居偏偏过来聊天。
第2个回答 2013-04-16
这是规律,你要死记住的
.某些特殊句型的反意疑问句:
1)祈使句的反意疑问句:
表示肯定意义的祈使句,即表示“请求,提示”它的反意疑问句用will you 表达:有时也可以用won’t you 表示。
Go home now, will you ?
Close the window, please, will you ?
否定祈使句:以Don’t开始的祈使句:表示“不要……”,用will you 提问:
Don’t be late again, will you ?
Don’t forget to pay your income tax, will you ?
Let’s引导的祈使句表示“建议”,反意疑问句部分是:shall we ?
Let’s go for a walk, shall we ?
Let’s have a rest now, shall we ?
Let me 或 Let us引导的祈使句表示“请求”,反意疑问句部分为will you:
Let me have a try, will you ?
Let us help, will you ?
2) 感叹句的反意疑问句:一律用否定式提问。
What a clever boy, isn’t he ?
What a lovely day, isn’t it?
3) 陈述句含有情态动词must有两种情况:
must表示“必须”,反意疑问句部分为mustn’t…? / needn’t…?
He must study hard at English, mustn’t he? / needn’t he?
You must go home now, needn’t you? / mustn’t you?
We mustn’t be late, must we ?
Must表示推测:“一定,肯定” 反意疑问句部分与must后面的动词呼应
You must be joking, aren’t you?
He must be ill, isn’t he ?
注意:用must对过去的动作推测时,反意疑问句部分的助动词用did或have, 而对过去的状态推测,反意疑问句部分的be动词用was:
She must have finished her work, hasn’t she ? / didn’t she ?
Jack must have arrived here yesterday, didn’t he ?
He must have been a policeman, wasn’t he ?
4) 陈述句中有否定副词:hardly; never; seldom; little; few; nowhere; nothing等词,反意疑问句部分用肯定提问:
Frank hardly goes to parties, does he ?
He has few friends, has he ?
5)复合句的反意疑问句:大多数复合句的反意疑问句都对主句提问:
He was punished because he violated the regulation, wasn’t he?
You never told me that you had been ill, did you ?
注意:I don’t think/suppose/believe/imagine 引导的宾语从句,这种宾语从句的反意疑问句应与从句的主语,谓语部分一致,而且用肯定式的提问。
I don’t suppose anyone will volunteer, will they ?
I don’t believe she has done it, has she ?
I think he will come. won’t he?