i hear him singing a song变被动语态

题目

i hear him singing a song变被动语态
he can't buy me a coat
will he finish reading the book
we see them go into the shop

答案

正确答案为：
1 He is heard to sing a song by me.
2 A coat can't be bought for me by him.
3 Will the book be finished reading by him?
4 They are seen to go into the shop by us.