Переделать из действительного залога в страдательный залог.
1) The teacher explaing new material at every lesson.
2) The teacher is explaing new material now.
3) The teacher has been explaining new material for 10 minutes since 9 o'clock in the morning.
4) The teacher explained new material yesterday.
5) The teacher was explaining new material yesterday at 10 o'clock.