英语语法选择题,请大家看看该怎么做

英语语法选择题,请大家看看该怎么做
1.If I see the twin brothers apart I don't know ( ).
A. who is who B. who is whom C.which is which D. what is what
2.His advice has made the design bettter than it ( )
A. would otherwise have been B.would be otherwise C.has otherwise than D.had otherwise been
3.You must have seen him yesterday.( )?
A.mustn't you B.haven't you C.didn't D.don't you
4.As to the lost world of Egypt, we know nearly everything ( ) to know.
A.what is B.which is C.it is D.there is