as it turned out to be a small house party,we ______ so formally.A.needn't dress upB.shouldn't dress upC.were not necessary to dress upD.needn't have dressed up 为什么不选c

问题描述:

as it turned out to be a small house party,we ______ so formally.
A.needn't dress up
B.shouldn't dress up
C.were not necessary to dress up
D.needn't have dressed up 为什么不选c