—Where is that report?—I brought it to you you were in Mr. Black’s office yesterday.A. if

问题补充：

—Where is that report?

—I brought it to you you were in Mr. Black’s office yesterday.

A. if

B. because

C. when

D. before

答案：

A. if

B. because

(答案→)C. when

D. before

解析：词义辨析题。A. if如果 B. because 因为C. when当…时候 D. before 以前句意：“那份报告在哪？”“昨天当你在布莱克先生的办公室的时候我把它给你带来了。”根据语境选C