1、__________,I shoud ask them some question.

1、__________,I shoud ask them some question.
A.Shoud they come to us B.If they come to us
C.Were they come to us D.Had they come to us
正确答案是A,请问是为什么?
2、You ought to know better than ________yourself in unnecessary expense.
A.to involve B.involve C.involving D.involved
正确答案是A,请问是为什么?
3、It was in that small room________they worked hard and dreamed of better days to come.
A.where B.in which Cwhich .D.that
正确答案是D,请问为什么?
4、The doctor advised that Tom an operation right away so as to save his life.
A.had B.would have C.have D.was going to have
请问为什么?
The doctor advised that Tom____________an operation right away so as to save his life.