不定式的基本形式就是to do,非谓语动词的一种.
主要用法：1.做某些动词的宾语,像want,decide, ask, pretend, help, desire, agree, offer, hate, like, fail, attempt, choose, manage,etc.
eg. He decided to do the work by himself.
The prisoner attempted to escape,but failed.
2. 做状语时,表目的和结果.
To learn English well, you should do more exercises.
He searched the room only to find nothing.