动词不定式用法!急

动词不定式用法!急
1.I prefer __ more money for a better car rather than pay less for this one.
A./ B.offering C.offer D.to offer
2.He did what he could __ us with our English.
A.help B.helps C.to help D.helping
3.we are told ___ everywhere .It's our duty to keep our school clean and tidy.
A.not to make much noice B.to spit C.to draw D.not to throw waste paper
4.I was sad ___ away.
A.seeing her go B.to see her to go C.to see her go D.saw her go
5.Will you please ___ me ___ some cleaning this evening?
A.to help;to do B.help;to do C.help;with do D.to help;do
6.We have two rooms ___ ,but I can't decide ___.
A.to live;to choose which one B.to live in;which one to choose C.lived;choose which one D.live;which one to choose
最主要的是注明为什么!