–What should I do doctor? healthy you should take more exercise.A. KeepB. KeepingC. T

问题补充：

–What should I do, doctor?

-- healthy, you should take more exercise.

A. Keep

B. Keeping

C. To keep

DKept

答案：

A. Keep

B. Keeping

(答案→)C. To keep

D. Kept

解析：考查动词不定式。句意：----医生，我应该做什么？---为了保持健康，你应该多做锻炼。故选C。这里动词不定式做目的状语。