省to 的动词不定式
  
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.