He took medicine 3 times a day, didn't work.A. itB. butC. whichD. but which

网友回答

A. it
B. but
(答案→)C. which
D. but which
解析：句意：他一天吃三次药，这不奏效。这里需要非限制性定语从句，用which引导，指代前面的句子，在定语从句中which做主语，如果用but连接并列句，应该是but it…，所以选C。