I used to go to the gym three times a week, but I don’t any more.
A. work on
B. work at
C. work out
D. work for
网友回答
A. work on
B. work at
(答案→)C. work out
D. work for
解析：考查动词短语：A. work on从事，忙于，B. work at致力于，C. work out 锻炼，制定出，结果是，D. work for为…工作，句意：我过去一个星期去三次健身房，现在我不去锻炼了。选C。