Решение:
- 1. Students use computers at their lessons. -> Computers are used by students at their lessons. (Компьютеры используются студентами на уроках).
- 2. The teacher explained the rules of the game to the students. -> The rules of the game were explained to the students by the teacher. (Правила игры были объяснены студентам учителем).
- 3. They will clean the office tomorrow. -> The office will be cleaned tomorrow. (Офис будет убран завтра).
- 4. Mary has bought a car. -> A car has been bought by Mary. (Машина была куплена Мэри).
- 5. My mum made a cake yesterday. -> A cake was made by my mum yesterday. (Торт был сделан моей мамой вчера).
Ответ: 1. Computers are used by students at their lessons. 2. The rules of the game were explained to the students by the teacher. 3. The office will be cleaned tomorrow. 4. A car has been bought by Mary. 5. A cake was made by my mum yesterday.