问题补充：
It was announced that only when the terrible disease was under control to return to
their homes.
A. the residents would decide
B. would the residents decide
C. would the residents be decided
D. the residents would be decided
答案：
A. the residents would decide
(答案→)B. would the residents decide
C. would the residents be decided
D. the residents would be decided
解析：考查部分倒装句：only+副词，介词短语，状语从句放在句首时，主句谓语用部分倒装，将be动词，助动词，情态动词放在主语前面，这句话only后面接时间状语从句，位于从句的句首，后面的主句要倒装。句意：人们宣布只有当可怕的疾病被控制住，居民才决定回家。the residents 和decide是主动关系，选B。
