四、不定式用作宾语补足语
Who taught you to drive? 谁教你开车的?
He warned me not to touch it. 他警告我不要碰它。
What caused him to change his mind? 什么使他改变主意的?
五、不定式用作定语
I have a question to ask you. 我有一个问题要问你。
It is a pleasant thing to remember. 这是一件值得记住的愉快的事。
He is not a man to tell a lie. 他不是个说谎的人。
【注】有的名词(如way, chance, right等)后用作定语的不定式可换成of doing sth：
It’s the best way to do [of doing] it. 这是做此事最好的办法。
但是，以下名词后接不定式作定语时通常不能换成of doing sth：
attempt 试图 courage 勇气
decision 决定 effort 努力
fortune 运气 failure 失败
invitation 邀请 permission 允许
promise 允诺 wish 愿望
六、不定式用作状语
不定式作状语可以表示多种关系(如目的、结果、原因、条件等)：
I went to France to learn French. 我到法国去学法语。(表目的)
He returned home to find his wife waiting for him. 他回到家发现他的妻子在等他。(表结果)
You would make a great mistake to accept his offer. 你要是接受他的建议，你就犯了大错误。(表条件)
We are proud to be members of this team. 作为这个队的队员我们感到很自豪。(表原因)
He opened his mouth as if to say something. 他张开嘴，好像要说什么。(表方式))