完形填空。
Almost all people think exercising is good for us. But how often should (应该) we exercise? Five days week? Four days week? Is two days week 1? Luckily, the answer 2 the question is not difficult to find.
We asked Shawn Arent, a scientist (科学家), about this question. He said that people should 3 every day. It really does great help to our 4 and health.
Shawn also told us 5 more interesting "There is a big 6 between exercising two days a week and three days a week," Shawn said. "With three days a week, your body gets enough exercise and you want to do 7 activities to be healthier (更健康的). 8, with two days week, you don't get much change (改变). You just don't do it often enough, so you can't fully (完全地) 9 the fun of exercising.
"For children and old people, it's a good start to exercise two days a 10 at first. But I still want them to exercise more after some time. Three to four days a week will be wonderful for them," Shawn said.