Переделайте предложения в passive voice. Who has written this poem? When will they hold the annual dance? They are developing

Answers: 

Whom this poem has been written by?

When will the annual dance be held by them? 

Whom is a film being developed by?

How often should the fish be fed? 

Пояснения: пассивный залог строится при помощи вспомогательного глагола \"to be\"  и основного глагола с окончанием -ed, либо 3 формы глагола из таблицы неправильных глаголов.