By the time the police came to rescue the old woman she for four days under the house.A.

问题补充：

By the time the police came to rescue the old woman, she for four days under the house.

A. buried

B. had buried

C. had been buried

D. has been buried

答案：

A. buried

B. had buried

(答案→)C. had been buried

D. has been buried

解析：考查时态及语态。By the time+ 一般过去式的句子，后面的主句应用过去完成时态，句意：到警察来就这位老妇人的时候，她已经在房子下面被埋了四天了。根据语境应用过去完成时态的被动语态。故选C。