时态
1.Imagine
2.drops,will break
3.leaves,will be
被动语态
1.A long time ago fire was used for cooking food by man.
2.Letters aren't written by us in English.
3.I am always made to cry by him.
4.A complaint was rarely received by him.
5.The captain was seized and dragged away by them.
6.She was heard singing a beautiful song by us yesterday.