题目

任务型阅读As we all know, in daily life, many people want to get in shape. If you happen to be one of them, where will you get started?Diet comes first. Health experts have long noted the importance of physical activities. Physical activity burns calories—the more calories you consume, the easier it is to control or lose your weight. Besides, it helps to reduce the risk of some diseases, including heart disease, stroke and even some kinds of cancer.Physical activity is also known to increase the release of endorphins, which help people to reduce pain and feel more happy and peaceful as在“性状分离比的模拟”实验中，某同学连续抓取三次，小球的组合都是Dd，则他第4次抓取Dd的概率是A．1/4B．1/2C．0D．1