1.You wouldn't have seen her if it----not been for him

1.You wouldn't have seen her if it____not been for him
B.had
用了虚拟语气吗
2.She insists that he____ his vacation now.
C.take
这题为什么用原型呀?不用加S?
3.Even though she herself has never had such an experience,it's___ she can recongize from what has happened to her good friend.
A.that B.when c.such d.all
这题为什么选C呀?
4.Only agter the storm was over _______
a.could we start off
b.we could start off
c.had we started off
d.we had started off