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 the residents be permitted
D. the residents had been permitted
网友回答
A. the residents would be permitted
B. had the residents been permitted
(答案→)C. would the residents be permitted
D. the residents had been permitted
解析：本题考查倒装句。根据句中的only when the fire was under control结构可以立刻看出本题考查的是倒装结构，因此首先排除答案A 、D; 再根据句意“据宣布，只有当大火得以控制，居民们才被允许回到他们的家”判断主句的动作含有过去将来时的含义，因此选择C。