HELP!这些题目看了参考答案仍然不知为何要选它.请兄弟姐妹们帮忙详细告知一下原因.THANK YOU VERY MUC

HELP!这些题目看了参考答案仍然不知为何要选它.请兄弟姐妹们帮忙详细告知一下原因.THANK YOU VERY MUCH
HELP!这些题目看了参考答案仍然不知为何要选它.请兄弟姐妹们帮忙告知一下原因.THANK YOU VERY MUCH!
1.If you had done as i told you,this______.
a.should have not happened b.would not have happened c.did not happen d.had not happened
2._________no friction between the surface of the road and our feet,we could not walk at all.
a.If ther was b.Were there c.Was there d.There was
3.Henry _________a rich man today if he had been more careful about his investment in the past.
a.would be b.is c.will be d.would have known
4.She would go and inform him if she ______his address.
a.know b.had known c.knew d.would have known
5.For a while everyone was screaming,tugging,beating and kicking and then Mother came in from the kitchen and said firmly,"_________!it's time for a rest."
a.Do b.Have done c.Doing d.Done
6.The consequences of this ill-advised policy are already known to all of us here,_______to say that we have suffered more losses in this month than in the three previous years.
a.it suffice b.suffices it c.suffice it d.it is suffice
7.An old friend of his stayed the whole day with him and thought out several conjectures about the possible reasons for his son's diasppearance.The por father listened and repeatede in a low voice,"________so!"
a.Be it b.It be c.It is d.Is it
8.The general stood up and looked at the president menacingly," Ican bring in 50,000 troops to the capital if ________."
a.is need b.need is c.were need d.need be
1.Getting more and more impatient the coach shouted at his players " Tom stays to the right!Peter runs to the front!Everybody is quick!"
2.Our sanction against your son is by no means irreversible.Behave himself and he will be allowed to come back to the classroom.
1-8 caad bcad
改错题 1.Peter runs……句中的runs 改为run.
2.Behave himself……句中的Behave 改为If he behaves……
主要是前四题。我认为的答案是bbdc。caad
改错题，还是不能够理解参考答案为何这么改。

参考答案是错误的.
正确的应该是baac ddc
第8题理解不能.
改错
1 everybody to be quick
2 come back to classroom