讲义
must

必须；义务＝have to/have got to (过去式为had to)

(否定为need not/don't have to/don't need to)

We must (= have to) obey the law. 我们必须守法。

All the drivers must wear seatbelts. 所有的驾驶员都必须系安全带。

The little boy must (= has to) keep quiet in the theater.

在戏院里小男孩必须保持安静。

It's getting late. I really must go. 天晚了，我真的得走了。

Must I make a reservation in advance?

No, you needn't/don't have to.

Do I have to make a reservation in advance?

Yes, you do./No, you don't.

我必须事先订位吗？ 不必。