题目

A lot of people play sports, but very few people become sports professionals (专业人员). If sports aren't going to be your future, then why should you play them? Why should you train every day? Why should you work hard and feel sore (酸痛) the next day? Wouldn't it be better to forget sports and only pay attention to your lessons?There are actually a lot of good reasons to play sports. First of all, sports are a great way to exercise. Exercising keeps you healthy and strong. It also helps you stay in a good state. When you exercise, your body produces endorphins (内啡肽). Endorphins g下列计算正确的是（ ）A．-24=16B．C．D．