Sit down Emma. You will only make yourself more tired on you feet.A. to keepB. keepingC.

问题补充：

Sit down, Emma. You will only make yourself more tired, on you feet.

A. to keep

B. keeping

C. having kept

D. to have kept

答案：

A. to keep

(答案→)B. keeping

C. having kept

D. to have kept

解析：