Such a difficult problem__that I don't know what to do with it.A.it is B.was it C.is it D.it was

问题描述:

Such a difficult problem__that I don't know what to do with it.
A.it is B.was it C.is it D.it was

C。

A

C such或者so放在句首,要使用倒装.再根据时态,所以用C
She is so pretty.= So pretty is she.