---How can you keep slim as a mother of two sons?---I in the gym for years.A. have worked

问题补充：

---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

答案：

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。