I looked everywhere in the house a key that had been lost.A. in searching forB. in search

问题补充：

I looked everywhere in the house a key that had been lost.

A. in searching for

B. in search of

C. to search

D. searching of

答案：

A. in searching for

(答案→)B. in search of

C. to search

D. searching of

解析：考查短语：in search of寻找，search for寻找，句意：在房子里我到处看了看寻找丢失的钥匙。所以选B。