问题补充：
---- Did he give you advice on your work yesterday?
---- Yes. But his advice, as a matter of fact, my difficulty.
A. used to
B. related to
C. added to
D. belonged to
答案：
A. used to
B. related to
(答案→)C. added to
D. belonged to
解析：短语used to过去常常；relate to涉及，与…有关；add to增加；belong to属于…；句义：—昨天他有没有给出一些关于你的工作的建议？—是的，但是实际上他的建议增加了我的困难。根据句义说明C项正确。
