—Where were you both at this time last night?—Tom was writing an e-mail I was watching TV

问题补充：

—Where were you both at this time last night?

—Tom was writing an e-mail I was watching TV at home.

A. as soon as

B. after

C. until

D. while

答案：

A. as soon as

B. after

C. until

(答案→)D. while

解析：as soon as一……就；after在……之后；until直到……时；while一边……一边，强调动作的同时发生。句意：昨晚这个时候你们两个在哪儿？——汤姆在写电子邮件，我在家看电视。动作同时发生，故选D。