In the office I never seem to have time until 6．p．m．，________ all my workmates have gone home．

In the office I never seem to have time until 6．p．m．，________ all my workmates have gone home．

A.that

B.which

C.Whose time

D.by which time

答案及解析： D

解析：

考查定语从句。by which time到…时候，因为是定语从句，故用by which time．