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

问题补充：

---What should I do, doctor? ---healthy, you should take more exercise.

A. Keep

B. To keep

C. Keeping

D. To keep away from

答案：

A. Keep

(答案→)B. To keep

C. Keeping

D. To keep away from

解析：句意：医生，我应该怎么做呢？为了保持健康，你应该多做锻炼。句中动词不定式表目的，作目的状语放在句首，故选B。