请认真阅读下列短文,并根据短文的内容要点完成文章后的表格.注意:补全填空应符合语法和搭配要求,每空只填一个单词.
We all need physical exercise. Exercise uses up food we eat and keeps the body full of energy.
It works your muscles and makes your heart work hard so as to send blood to your muscles. So,
exercise makes your heart and muscles strong. Exercise also makes you feel refreshed. If you exercise
a couple of times a week, you will stay happy and healthy.
Some Western countries, such as the United States, have problems with exercise. In the US, many
people don't have enough exercise because it is hard for them. People have to work from dawn till dusk,
so they don't have time to take exercise. They work in office buildings sitting in chairs all day long in
front of computers. They cannot get much exercise sitting at desk passively.
Some Westerners can get exercise walking from their homes to work. However, the majority of
people cannot do this. It is too far from their homes to their offices. They have no choice but to drive
to work. In fact, some have to drive one or two hours to their offices. This is unfavorable in two ways.
First, these people don't have a chance to exercise because they are sitting in their cars for two to four
hours each day. Second, driving is challenging especially in rush hours and calls for too much attention.
It makes a person worn out. So, when these people arrive home at night, they don't have the desire to
take exercise after work.
Today, many people in the West 
are overweight, which causes health problems for them. Doctors
say exercise can help people both lose weight and improve their health. So many people are trying to
get more exercise. But it takes time to change, and when people don't see a difference right away, they
will lose heart and stop exercising.
倍。设太阳帆的反射系数ρ=0.8，太阳帆为圆盘形，其半径r=15m，飞船的总质量m=100kg，太阳光垂直照射在太阳帆表面单位面积上的辐射功率P0=1.4kW，已知光速c=3.0×108m/s。利用上述数据并结合第（2）问中的结论，求太阳帆飞船仅在上述光压的作用下，能产生的加速度大小是多少?不考虑光子被反射前后的能量变化。（保留2位有效数字）
(2)
(3)
2分
2分
1分
2分
1分
1分
2分
1分