I often watch CCTV-9, I have learned a lot of new words and expressions.
A. from which
B. of which
C. to which
D. which
网友回答
(答案→)A. from which
B. of which
C. to which
D. which
解析：考查非限制性定语从句。“从......学到......”learn sth. from ...；“我经常看中央9频道，我已经从中央9套学到了很多新词和短语。”根据介词from排除B、C、D。故选A。