请各位英语高手帮我看看,作业上的题,觉得答案有点问题.

请各位英语高手帮我看看,作业上的题,觉得答案有点问题.
1、This machine is very easy to use.()can learn to use it in a very short time.
A.Somebody B.Anybody C.Nobody D.Few people.
2、He did not raise his head until someone slapped him (填个介词)the back.
3、-How much do you know about the ancient Chinese tombs?
-I only know they faced south and had mountains()the back.
A.atB.in
(2、3两题一个答案是on,一个是at,矛盾吗?）
4、-Whose bike is this?
-It()be Jane's.Because her schoolbag is sill(不知道是不是作业印错了这个单词）on it.
A.must B.cannot
5、-Best wishes（）your Food Festival.
-Thanks,and give my best wishes()your family
A.for toB.to toC.for forD.to for
6、I made chicken for you. Is it OK ()you?
A.with B.for.
7、There will be two()in the school hall at the weekend.
A.fashion showsB.fashions shows
C.fashion show D.fashions show
8、-Kate,do you know()it is from her to the gym?
-About twenty-minutes' walk.
A.how long B.how soon C.how often D.how far
可以分别解释一下吗？？？谢谢谢谢谢谢！