CET4语法：不定式符号的省略

　　1)使役动词make, let, have和感官动词hear, listen to, look at, see, observe, watch, notice等接动词不定式时，省略to。

　　【例如】

　　My husband let me wash his clothes and iron his tie yesterday.The sad movie made me cry.I saw him leave the room and disappear.

　　2)在had better(最好)和would rather(宁愿)后面，直接加动词原形。

　　【例如】

　　You'd better inform me of what has happened.

　　I would rather do it myself than ask for your help.

　　3) rather/sooner than(宁可…而不)位于句首时，可直接加动词原形。

　　【例如】

　　Rather than do it by himself, he asked for his mother's help.Sooner than marry that man, she would make a living as a servant.

　　4)主语部分含有do时，作表语的不定式省略to。

　　【例如】

　　What we can do now is just wait.The only thing I can do is work hard and pass the exam.

　　What I advise you to do is go to the hospital and have a thorough examination.

　　5)以all, all that ,the＋形容词最高级或the only (first, last) thing作主语，加一个do为谓语动词的定语从句，这时系动词be后面作表语的不定式可省略to.

　　【例如】

　　All I could do/the only thing I can do was give him a little money.

　　6)主语是thing或way时，由不定式to do修饰，作表语的不定式也可以省略to.

　　【例如】

　　The best thing to do is find a really qualified person to replace him.