简介
动词不定式是学习英语的难点之一，也是构成长句的一个重要因素。不定式有自己的宾语、状语和补足语，组成不定式短语。在分析句子时要把不定式短语看作一个整体。不定式在句中可作主语、表语、宾语、定语、状语和补足语。
作宾语
He pretended not to see me.n
他假装没看见我。（不定式短语not to see me作宾语。）n
I haven't decided whether to sell it or not.n
我还没有决定是否卖它。（不定式短语whether to sell it or not作宾语。）n
I find it difficult to understand him.n
我发现很难理解他。（不定式短语to understand him作真正宾语，it是形式宾语。）
作补语
My idea is to climb the mountain from the north.n
我的意见是从北面爬上山。（不定式短语to climb the mountain from the north作主语补语。）n
The teacher asked me to open the window.n
老师要我打开窗户。（不定式短语to open the window作宾语补语。）
作修饰语
I have no wish to quarrel with you.n
我不想和你吵架。（不定式短语to quarrel with you作名词wish的修饰语。）n
He ran to catch the bus.n
他跑步去赶公车。（不定式短语to catch the bus作动词ran的修饰语。）n
Henry was happy to hear the news.n
听到这个消息亨利很高兴。（不定式短语to hear the news作形容词happy的修饰语。）
时态/语态n
一般时 to do to be donen
进行时 to be doingn
完成时 to have done，to have been donen
完成进行时 to have been doing
作表语
动词不定式做表语，一般用于be动词或seem等系表动词后面。主语通常是wish，idea，works，task，job，aim等词。
