单选题 Many people do not engage in physical exercise mainly because ______.
【正确答案】 C
【答案解析】本题问：“许多人不参加体育锻炼的原因是什么?”我们可以从第二段simply because they don't think they are in need of it (仅仅是因为他们觉得他们不需要)中找到答案。