Question

you ... the room since I was there for the last time?
a) Have ... painted
b) Have... been painted
c) Were ... painted
Our timetable ... by the headmaster last month.
a) has been changed
b) was changed
c) was change
When I arrived the dinner... already cooked. a) has cooked
b) were cooked
c) had been cooked​

Answer 1

Ответ:

1. Have you been the room since I was there for the last time? (b выбрали)

2. Our timetable was changed by the headmaster last month. (b)

3. When I arrived the dinner had been already cooked. (c)

Объяснение:

если есть предлог "since", то используется время Present Perfect Continuous; если есть предлог "by", то нужен пассивный залог, и время здесь простое прошедшее, потому что это однократное действие; в третьем там нужен пассивный залог, потому что ужин не может сам себя приготовить, остальные формы грамматически неправильны.