they __to enter the building by the back door:however,the front door was locked.A weren not supposed Bwould not be supposedCwere supposedDwould be supposed
问题描述：
they __to enter the building by the back door:however,the front door was locked.
A weren not supposed
Bwould not be supposed
Cwere supposed
Dwould be supposed
答
A 他们不应该是是从后门进来的,但是,前门是锁的啊.