Помогите с пассивным залогом
Упражнение 28. Заполните пропуск, выбрав подходящую форму глагола в страдательном залоге.
1. The basic statements of classical economy ________ by Adam Smith.
a) were formulated; b) was formulated; c) formulated; d) will formulate
2. Who ______ this book ______ by? – Its author is Mark Twain.
a) was … written; b) has … written; c) was… writing; d) were … written
3. The students _________ about the college regulations.
a) were telling; b) was told; c) were told; d)has told
4. What about the new theatre? – It _______ by the end of the year.
a) was constructed; b) will be constructed; c) has been constructed; d) will have been constructed
5. Much work ________ already ________ by this research center.
a) was … being done; b) has … been done; c) had … been done; d) was … done