—What should I do doctor? —healthy you should take more exercise. A. To keepB. KeepC. Ke

问题补充：

—What should I do, doctor?

—healthy, you should take more exercise.

A. To keep

B. Keep

C. Keeping

D. Kept

答案：

(答案→)A. To keep

B. Keep

C. Keeping

D. Kept

解析：句意：医生，我该怎么做？——为了保持健康，你应该多参加锻炼。不定式做目的状语表示具体的将要进行的动作，结合语境可知选A。