The dangers of sitting all day are

The dangers of sitting all day are obvious. Researchers have shown that remaining sitting for extended periods of time (like at your 9-to-5 desk job) can do harm to your health. While exercise is a big part of reducing the harmful effects of sitting, it was unclear how many gym periods were needed to help – until now.A new study, published in The Lancet, shows the ideal formula for reducing the negative effects of a sedentary（久坐的）job. Instead of a fixed number of hours spent exercising, the ratio（比率）depends on how much you sit: people who work a typical eight-hour day should spend at least one hour each day moving. If you sit six hours a day, you should spend half an hour exercising. The research also indicates that the exercise doesn’t have to be all once – or rigorous（严格的）. It can be spread throughout the day and be as simple as walking.The team behind the study analyzed data from a pool of a million adults over the age of 45 in Western Europe, the United States, and Australia. Using previous data, the researchers examined data from 16 published studies and used it to determine how much exercise is required to compensate for sitting. Their recommended daily exercise goal is higher than previous advice but not necessarily less achievable, given it can be completed throughout the day.Fitting in an hour of exercise a day sounds especially discouraging if you have a desk job, but there are plenty of workouts you can complete before and after work. Even if it means taking a 10-minute walk during lunch, your body will thank you in the long run.21. The underlined words “compensate for” can be best replaced by ________.A. make up for B. break away fromC. give up D. take the place of22. According to the new study, good news for the people working long hours at desk is that ________.A. workouts may reduce the harm of sitting for longB. the harm of sitting for long has been provedC. they don’t have to exercise as long as suggested previouslyD. the time spent on exercise is flexible23. What can be inferred from the article?A. The best form of workouts is walking.B. The longer you exercise, the better.C. The new exercise goal is practical though higher.D. A desk job makes it impossible to exercise regularly.24. The second paragraph is developed mainly ________.A. by example B. by processC. by comparison D. by contrast