所有乘客都要系安全带。

All passengers must wear seat belts.

法律命令所有司机系安全带。

The law mandates that all drivers wear seat belts.

每个人在车里必须系安全带。

Everyone must wear a seatbelt in the car.

开车时系安全带是强制的。

It is compulsory to wear a seatbelt while driving.

车内每个人都必须系安全带。

Everyone in the car must wear a safety belt.

开车时系安全带是强制性的。

It is obligatory to wear a seatbelt while driving.

他忘记系安全带，被警察罚款了。

He forgot to wear his safety belt and got fined by the police.

请在开车前系安全带。

Please belt up before driving.

不系安全带开车是危险的。

It's dangerous to drive without a seatbelt.

不系安全带开车是愚蠢的。

It's idiotic to drive without wearing a seatbelt.