小题1:D
小题1:B
小题1:A
小题1:D
小题1:C
小题1:根据How to Become Fit?如何变得健康？及下文描述可知选D如何保持健康。
小题1:根据If you have the correct number of及下文you will lose weight, 可知选B为最佳答案。
小题1:根据Experts suggest that teenagers spend at least 30 minutes exercising, five times a week.30*5=150故选A。
小题1:根据Healthy eating habit along with regular exercise is the only way to become fit. 可知选D。
小题1:根据teenagers often give up sports, saying they have no time left after their studies.可知是学生忙于学习，故选C。