buy-have join-be in leave-be away
borrow-keep break-be broken die-be dead
open-be open close-be closed get up-be up
become-be come-be there begin-be on
lose-be lost marry-be married go-be away
vii. 过去完成时
had done
表示过去某一时刻或动作以前已经发生或完成了的动作，对过去某一点造成影响或结果
viii. 过去将来时
would do
was/were going to do
表示在过去的某一时间来看将来要发生的动作或呈现的状态
III. 动词不定式
非谓语动词
作主语
It is + n.(+for sb.)+ to do sth.
It is + adj.(+for sb.)+ to do sth.
It is + adj. of sb.+ to do sth.
与疑问词连用 How to do it?
做宾语
v. + to do
want like love need try ask learn begin start forget remember hope wish agree fail decide afford offer plan hate try one's best choose
