不得

不得

"不得" means "must not" or "cannot."

This usage of '不得' means 'must not' or 'not allowed to', expressing prohibition.

学生不得在课堂上玩手机。

Students must not use their phones in class.

Here '不得' signifies a strict prohibition against an action, often used in formal or legal contexts.

这些信息不得泄露。

This information must not be disclosed.

In this case, '不得不' forms a fixed expression meaning 'have to' or 'no choice but to', indicating necessity or compulsion.

由于天气原因，航班不得不被取消。

Due to weather conditions, the flight had to be canceled.