In the office I never seem to have time until after 5:30 pm many people have gone home.

问题补充：

In the office I never seem to have time until after 5:30 pm, many people have gone home.

A. that

B. which

C. whose time

D. by which time

答案：

A. that

B. which

C. whose time

(答案→)D. by which time

解析：

D。by which time 引出的是一个非限制性定语从句，其中 by which time 相当于 and by that time。