24 You must/can't wear a seatbelt when you're in a car. That's the law. 25 You must/mustn't eat in the library. It's forbidden.

24. You must wear a seatbelt when you're in a car. That's the law. (Вы должны пристегиваться ремнем безопасности в машине. Это закон.)

25. You mustn't eat in the library. It's forbidden. (Вам нельзя есть в библиотеке. Это запрещено.)