不定式动词：to的动词不定式

　　不定式动词主要包括以下类别：

　　1)情态动词(除ought外，ought to)：

　　2)使役动词let,have,make：

　　3)感官动词see,watch,look at,notice,observe,hear,listen to,smell,feel,find等后作宾补，省略to。

　　注意：在被动语态中则to不能省掉。

　　I saw him dance.

　　=He was seen to dance.

　　The boss made them work the whole night.

　　=They were made to work the whole night.

　　4)would rather，had better：

　　5)Why…/why not…：

　　6)help可带to，也可不带to,help sb(to)do sth：

　　7)but和except：but前是动词do时，后面出现的动词用不带to的动词不定式。

　　8)由and,or和than连接的两个不定式，第二个to可以省去：

　　9)通常在discover,imagine,suppose,think,understand等词后，可以省去to be：

　　He is supposed(to be)nice.他应该是个好人。

　　举例：

　　He wants to move to France and marry the girl.

　　He wants to do nothing but go out.

　　比较：He wants to do nothing but go out.

　　He wants to believe anything but to take the medicine.

　　典型例题

　　1)----I usually go there by train.

　　----Why not ___ by boat for a change?

　　A.to try going B.trying to go C.to try and go D.try going

　　答案：D.why not后面接不带to的不定式，因此选D。

　　2)Paul doesn't have to be made ___.He always works hard.

　　A.learn B.to learn C.learned D.learning

　　答案：B.make后接不带to的动词不定式，当其用于被动时，to不可省略。