Jack spends much money on books he is not so rich.A. thoughB. whenC. ifD. because

问题补充：

Jack spends much money on books he is not so rich.

A. though

B. when

C. if

D. because

答案：

(答案→)A. though

B. when

C. if

D. because

解析：though虽然,尽管; when既然,当……时；if是否，如果；because因为。句意：尽管他不是很富有，杰克也花了很多钱买书。结合语境可知选A。