---Doing sports good for our health.Yes so I do morning every day.A. is exerciseB.

问题补充：

---Doing sports good for our health.

--- Yes, so I do morning every day.

A. is, exercise

B. is, exercises

C. are, exercise

D. are, exercises

答案：

A. is, exercise

(答案→)B. is, exercises

C. are, exercise

D. are, exercises

解析：句意：做运动对我们的健康有益。——是的，因此我每天做早操。上文主语Doing sports表达抽象含义，不可数，故谓语动词用单数。Exercise作名词讲时，是可数名词。结合语境可知下文早操表达复数含义，故exercise用复数形式，选B。