—Do you like doing sports Joe?—Of course. We can’t keep healthy taking enough exercise.A

问题补充：

—Do you like doing sports , Joe?

—Of course. We can’t keep healthy taking enough exercise.

A. without

B. by

C. for

D. With

答案：

(答案→)A. without

B. by

C. for

D. With

解析：句意：乔，你喜欢运动吗？当然，不进行足够的锻炼我们就不能保持健康。根据逻辑关系考虑应该用without，表示没有足够多的锻炼就不能保持健康；故选Ａ。