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

问题补充：

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

A. if

B. when

C. because

D. before

答案：

A. if

(答案→)B. when

C. because

D. before

解析：将四个选项逐一填入空格处，只有填when时，意思最通顺。句意为：当你昨天在布莱克先生办公室时我就带给你了。