must/mʌst/

v.

➊ used to say that it is necessary to do sth

➋ used to say that sth is likely based on information you have

否定缩略式

➭mustn't/'mʌsnt/

v. [M]

➊ 必须，应当：You must stop. 你必须停下来。

◇We must eat to live. 我们必须吃东西才能存活。

◇You mustn't tell him about it. 你不应当把这个事告诉他。

◇[must问句的否定回答用not have to或needn't] “Must you go?” “No, I don't have to.” “你必须走吗？” “不，我不必走。”

➋ 一定，必定：[对现在事情的猜测用现在时] You must be hungry. You haven't eaten all day. 你一定饿了，你一整天都没吃东西。

◇He must be there, isn't he? 他一定在那儿，是不是？

◇[对已经发生的事的猜测用完成时] He must have left. 他一定是离开了。

常犯错误

✗ It must be five now, mustn't it?

✓ It must be five now, isn't it?

[✌must表示猜测时，反意疑问句部分的助词据must后的动词确定]

音组-ust/-ʌst/

adjust; dust; just; must; trust

常犯错误

✗ “Must we do it now?” “No, you mustn't.”

✓ “Must we do it now?” “No, you needn't.” “我们必须现在做吗？”“不必要。”

[✌must一般疑问句的肯定回答用“Yes, you must.”否定用“No, you needn't.”或“No, you don't have to.”]

用法注意下列几句语气的差异：You must not leave. 你不准离开。You need not go. 你不必离开。You may not leave. 你可以不离开。

辨析have to; must