How can they learn anything they spend all their spare time watching television?A. forB.

问题补充：

How can they learn anything they spend all their spare time watching television?

A. for

B. when

C. while

D. because

答案：

A. for

(答案→)B. when

C. while

D. because

解析：考查状语从句连词。When=since既然。句意：既然他们把所有的时间都用在了看电视上，他们又怎么能学到东西呢？