问题详情

Fifty years ago, most peoples daily levels of activity were equivalent to walking three to five miles a day. Today, the【C1】______person fails to 【C2】______ that distance in a week. Its 【C3】______the ratio of fatness has soared—with serious implications for health. What we have【C4】______ in convenience from labour-saving devices over the past half-century, we have paid for【C5】______ a sharp decline in physical activity. We use cars, buses or trains to【C6】______ work; our children are 【C7】______ to school; elevators and lifts have replaced【C8】______stairs in shopping centres, offices and apartment blocks. Washing machines, vacuum cleaners, dishwashers and electric mowers all reduce the effort required to【C9】______a clean and tidy home. Almost one third of adults 【C10】______ over ten hours sitting down every day,adding【C11】______a staggering average of 32 years and four months over a lifetime. 【C12】______ surprising, then, that researchers 【C13】______this lifestyle. for our weight gain. Of course, our diets have changed, too, 【C14】______the fact is that we consume fewer calories now than in the 1960s. So what is the 【C15】______？ The secret is integrated exercise. This【C16】______going about your normal daily life—but doing it with enthusiasm. It might mean standing to【C17】______the phone and tapping your feet on the floor as you work. It means never taking the car when you could walk; it means standing on short train and bus【C18】______, or walking at a pace【C19】______you feel you might break into a run if you were to go any【C20】______.

【C1】

A．average

B．common

C．familiar

D．normal

请帮忙给出正确答案和分析，谢谢！