Not only( )working hard,but also( )very polite.A.is the boy,he is B.is the boy,is he.

Not only( )working hard,but also( )very polite.A.is the boy,he is B.is the boy,is he.
还有一题 -You seem to be an actor.
-( ).I have played many parts in a lot of films.
A.So am i B.So i am
（ he would have passed the exam.
A.If he studied hard B.Had he studied hard 答案写的是B 这题不是虚拟语气么，为什么要倒装？