You should answer my question in English. 你应当用英语回答我的问题。 They shouldn't be so careless. 他们不该如此粗心。 It's raining hard. You should drive slowly. 雨下得很大。你开车要慢些。
Modal Verbs (Ⅰ) must, may, should, will, have to
Studying the Rule
1) A: It’s hot, isn’t it? B: Yeah, but it may rain tomorrow.
2) A: May I sit on this chair? B: No, you mustn’t. A: Why not? B: Because it is broken.
e. g. He may know the answer． c. may用在感叹句中可表示祝愿、
愿望。 e. g.
May you succeed．(祝你成功。) May you have a pleasant journey．(一路平安。)
3. should是shall的过去式，它可以用 于过去时态中，但更多的是用作 情态动词，意思是“应当；应 该”，用来表示义务或责任。此 时，它不再局限于和第一人称的 代词连用，而是三种人称都能使 用。例如：
5) A: I have just walked 5 kilometers! B: You must be very tired now.
6) A: Will you give this to Elle, please? B: With pleasure.
7) A: It’s raining cats and dogs outside. B: Really? Then I have to take an umbrella with me.
should还可以用在提供帮助、提出建 议、要求、给予指示的句子中。 例如： Should I help you carry the basket? 要不要我帮你提篮子？ What should I do for them? 我应当为他们做些什么？ 应当注意的是，当should表示上述两 种意思时，要重读。
3) A: The flight to New York should be leaving in a few minutes.
B: Are you sure? 4) A: Sally, you should be careful
when you go out at night. B: OK, I will.
1. must与have to的区别 have to比较强调客观需要, must着重说明主观看法。另 外have to能用于更多时态, 比较下面的句子：
We had to be there at 10:00. 有时两者都可以用, 意思差别不大。 e. g. We must/have to leave now. must在表示说话人对事物的推测时 候要注意它比may肯定得多, 相当于 汉语的“一定”或“准是”A: Must I hand in the homework now? B: No, you don’t have to. You may hand it in tomorrow morning.
9) A: When are we going to leave the hotel?
B: We must leave the hotel before 6:00 pm.
5.如果对过去发生的事情的推测 要用完成时。
Someone must have opened the cage. The lion couldn’t have escaped on its own.
准是有人把笼子打开了，狮子不 可能自己跑出来。
一般疑问句的肯、否定回答
4. will 情态动词 aux. (客气提问)是 否愿意；…好吗 word that you say when you ask a polite question
·Will you pass the salt? 请你把盐递给我，好吗？
·Will you please give him a message when you see him? 你见到他时捎个口信给他好吗？
This must be your room． 在回答由must引起的问题时, 如 果是否定的答复，不能用 mustn’t, 而需要用needn’t或 don’t have to, 因为mustn’t是 “一定不要”的意思。
2. may的用法: a. 表示“允许”或“请
求”。 e. g. May I e in？
It can’t be Mr. Wang . He has left here. 3.may / might可用于肯定、否定句中
There may be some dangerous animals on the island.
4.should（想必）
They should be there by now.
·Won’t you e in and have a little tea? 要 不要进来喝点茶？
·Will you please lend me your rubber? 请借给我你的橡皮好吗？
表推测
1.must（一定）只用于肯定句中,
He looks so pale. He must be ill. 2.can / could用于肯定、否定、疑问句中,
在使用这一用法时需注意: may表 示“允许”的否定形式是must not, 意思是“不应该” “不许可”。e. g.
—May I take this book out of the reading-room？
—No, you mustn’t． b. 表示说话人的猜测，认为某一 事情“或许”或“可能”发生。