______ for your help, We’d never have been able to get over the difficulties.

A．Had it not

B．Had it not been

C．If it were not

D．If we had not been

合同的（）是指由于当事人在意思表示方面存在瑕疵而可以对已经成立的合同予以撤销或变更。

A.撤销

B.变更

C.注销

D.可撤销和可变更