You needn't finish that work today.

你不必今天做完这项工作。

Look, you needn't shout.

喂，你不必喊。

You needn't worry.

你不必担心。

Education needn't only be about furthering your career.

教育不必只是与推进你的事业有关。

I needn't add that if you fail to do as I ask, you will suffer the consequences.

我不必再说了，如果你不能按我说的做，你要承担一切后果。