If you want to be healthier you shouldnt do in the classroom all the time but do more

问题补充：

If you want to be healthier, you shouldn do in the classroom all the time but do more on the playground.

A. exercise; exercises

B. exercise; exercise

C. exercises; exercises

D. exercises; exercise

答案：

A. exercise; exercises

B. exercise; exercise

C. exercises; exercises

(答案→)D. exercises; exercise

解析：如果你想要更健康，你不应该一直在教室里做体操，而是在操场上做更多的锻炼。Exercise做锻炼和练习的意思讲时，是不可数名词；当做某种体操眼保健操等时是可数名词。结合语境可知选D。