-What should T do doctor? - healthy you should take more exercise.A. KeepB. To keepC. Ke

问题补充：

-What should T do, doctor?

- healthy, you should take more exercise.

A. Keep

B. To keep

C. Keeping

D. Kept

答案：

A. Keep

(答案→)B. To keep

C. Keeping

D. Kept

解析：句意：医生，我该怎么办？为了保持健康，你应该多做锻炼。动词不等式表示目的。故选B。