You need fit.A. exercise keepingB. to exercise to keepC. exercising keepingD. to exercise

问题补充：

You need fit.

A. exercise keeping

B. to exercise to keep

C. exercising keeping

D. to exercise keeping

答案：

A. exercise keeping

(答案→)B. to exercise to keep

C. exercising keeping

D. to exercise keeping

解析：句意：你需要锻炼来保持健康。动词不定式做宾语表示具体的将要进行的动作，不定式做目的状语也表示具体的将要进行的动作，结合语境可知选B。