[例4]— 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
【解析】答案D。why not 后面接不带to 的不定式，因此选D。
[例5]Paul doesn’t have to be made______.He always works hard.
A.learn B.to learn C.learned D.learning
【解析】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。相同用法的动词还有let，have，see等。
[例6]Tell him______the window.
A.to shut not B.not to shut C.to not shut D.not shut
