---How can you keep slim as a mother of two sons?
---I in the gym for years.
A. have worked out
B. have been working out
C. have worked on
D. have been working on
网友回答
A. have worked out
(答案→)B. have been working out
C. have worked on
D. have been working on
解析：句意：作为两个儿子的母亲你怎么能保持这么苗条？我这些年一直在体育馆锻炼。Work out锻炼，work on从事；. have been working out现在完成进行时，表示从过去一直到现在进行的动作，有可能还会进行下去。所以选B。