问题
选择题
It was announced that only when the fire was under control ___ to return to their homes.
A．the residents would be permitted
B．had the residents been permitted
C．would be residents be permitted
D．the residents had been permitted
答案
C
句意：据宣称只有当火势得到控制的时候，居民们才可以返回家中。Only+when从句放在句首时，用部分倒装。时态应用过去将来时。