Unit 3 课时作业19-【红对勾讲与练】2022-2023学年新教材高中英语必修第一册(人教版2019)

UNIT 3　SPORTS AND FITNESS　　　　　　　 课时作业 19 　 　 　 　 　 　 　 　 　 　Ⅰ. 阅读理解 Physical activity is important in preventing cardiovascular ( 心血管的) disease in young people so long as they don􀆳t undertake very intense activity on days when air pollution levels are high, according to a recently released study. Until now, little has been known about the relationships between the health benefits of physical activity taking place outdoors and the potentially harmful effects of air pollution. Previous research by the authors of the current study had investigated the question in middle- aged people at a single point in time, but this is the first time that it has been investigated in young adults aged between 20-30 years over a period of several years. In addition, the researchers wanted to see what happens when people increase or decrease their physical activity over time. At each health check-up, the participants completed a questionnaire asking about their physical activity in the past seven days and this information was changed into units of metabolic equivalent task (MET, 代谢当量任务) minutes per week ( MET-mins / week). The participants were divided into four groups: 0, 1-499, 500-999 and 1,000 or more MET-mins / week. People are recommended to do 500 - 999 MET-mins / week and this can be achieved by, for example, running, cycling or hiking for 15-30 minutes five times a week, or brisk walking, doubles tennis or slow cycling for 30-60 minutes five times a week. The researchers used data to calculate annual average levels of air poll