— You look pale. Did you sleep well？— No. It was already midnight I finished my homework.

问题补充：

— You look pale. Did you sleep well？

— No. It was already midnight I finished my homework.

A. before

B. when

C. that

D. since

答案：

A. before

(答案→)B. when

C. that

D. since

解析：句意：你脸色看起来很苍白，你睡好了吗？没有，当我完成作业的时候已经半夜了。when当…时候，引导时间状语从句，本题不难，故选B