7. Many experts point out that physical exercise contributes directly to a person's physical fitness.

　　许多专家指出体育锻炼直接有助于身体健康。

8. Proper measures must be taken to limit the number of foreign tourists and the great efforts should be made to protect local environment and history from the harmful effects of international tourism.

　　应该采取适当的措施限制外国旅游者的数量，努力保护当地环境和历史不受国际旅游业的不利影响。

9. An increasing number of experts believe that migrants will exert positive effects on construction of city. However，this opinion is now being questioned by more and more city residents，who complain that the migrants have brought many serious problems like crime and prostitution.

　　越来越多的专家相信移民对城市的建设起到积极作用。然而，越来越多的城市居民却怀疑这种说法，他们抱怨民工给城市带来了许多严重的问题，像犯罪和卖淫。

10. Many city residents complain that it is so few buses in their city that they have to spend much more time waiting for a bus，which is usually crowded with a large number of passengers.

　　许多市民抱怨城市的公交车太少，以至于他们要花很长时间等一辆公交车，而车上可能已满载乘客。

11. There is no denying the fact that air pollution is an extremely serious problem：the city authorities should take strong measures to deal with it.

　　无可否认，空气污染是一个极其严重的问题：城市当局应该采取有力措施来解决它。

12. An investigation shows that female workers tend to have a favorable attitude toward retirement.

　　一项调查显示妇女欢迎退休。

13. A proper part-time job does not occupy students' too much time. In fact，it is unhealthy for them to spend all of time on their study. As an old saying goes：All work and no play makes Jack a dull boy.

　　一份适当的业余工作并不会占用学生太多的时间，事实上，把全部的时间都用到学习上并不健康，正如那句老话：只工作，不玩耍，聪明的孩子会变傻。

14. Any government，which is blind to this point，may pay a heavy price.

　　任何政府忽视这一点都将付出巨大的代价。