Before starting the car, make sure you have fastened the seatbelt.

开车前 要确保安全带已经系好了

May I unfasten my seatbelt, now?

我现在可以解开安全带吗？

I can't open the seatbelt.

我打不开安全带。

I started wearing my seatbelt again.

我又开始系安全带了。

Bella: you should put your seatbelt on.

贝拉：你应该系上安全带。

Edward: you should put your seatbelt on.

爱德华：你才应该系上安全带。