4) there be+不定式

believe, expect, intend, like, love, mean, prefer, want, wish, understand

We didn't expect there to be so many people there. 我们没料到会有那么多人在哪里。

注意

有些动词需用as 短语做补语，如regard, think believe, take, consider.

We regard Tom as our best teacher.　我们认为汤姆是我们最好的老师。

Mary took him as her father .　玛丽把他当作自己的父亲。

3. 不定式作主语

1) It's easy (for me) to do that. 我做这事太容易了。

easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;

the first, the next, the last, the best, too much, too little, not enough

It's so nice to hear your voice.　听到你的声音真高兴。

It's necessary for you to lock the car when you do not use it. 当你不用车的时候，锁车是有必要的。

2) It's very kind of you to help us. 他帮助我们，他真好。

kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考虑周到的), silly, selfish(自私的)

It was silly of us to believe him.　我们真愚蠢，竟然相信了他。

It seemed selfish of him not to give them anything.　他不给他们任何东西，这显得太自私了。