Examples of public goods are not as rare as one might expect．A flood control dam(水坝) is a public good．Once the dam is built, all persons living in the area will benefit not thinking the respective of their own contribution to the construction cost of the dam．The same holds true for highway signs or aids to navigation(航海)．Once a lighthouse is built, no ship of any nationality can be effectively excluded from the utilization of the lighthouse for navigational purposes．National defense is another example．Even a person who voted against military expenditures(开支) or did not pay any taxes will benefit from the protection afforded.

    It is no easy task to determine the social costs and social benefits associated with a public good．There is no practicable way of charging drivers for looking at highway signs,  sailors for watching a lighthouse, and citizens for the security provided to them through national defense．Because the market does not provide the necessary signals, economic analysis has to be substituted for the impersonal judgment of the marketplace.

1．With what topic is the passage mainly concerned?

A．Mechanisms for safer navigation.

B．The economic structural of the marketplace.

C．A specific group of commodities.

D．The advantages of lowering taxes.

2．Which of the following would NOT be an example of a public good as described in the passage?

A．A restaurant.

B．A road sign.

C．A bridge.

D．A stoplight.

3．By which of the following could the word “holds”(in Paragraph 2)best be replaced?

A．has

B．grasps

C．remains

D．carries

4．According to the passage, finding out the social costs of a public good is a ________

A．difficult task.

B．daily administrative duty.

C．matter of personal judgment.

D．citizen’s responsibility.

5．Which of the following statements best describes the organization of the first two paragraphs?

A．Suggestions for the application of an economic concept are offered.

B．Several generalizations are presented from which various conclusions are drawn.

C．Persuasive language is used to argue against a popular idea.

D．A general concept is defined and then examples are given.

    Public goods(公众利益) are those commodities from whose enjoyment nobody can be effectively excluded(排除在外)．Everybody is free to enjoy the benefits of these commodities, and one person’s utilization does not reduce the possibilities of anybody else’s enjoying the same good.

    Examples of public goods are not as rare as one might expect．A flood control dam(水坝) is a public good．Once the dam is built, all persons living in the area will benefit not thinking the respective of their own contribution to the construction cost of the dam．The same holds true for highway signs or aids to navigation(航海)．Once a lighthouse is built, no ship of any nationality can be effectively excluded from the utilization of the lighthouse for navigational purposes．National defense is another example．Even a person who voted against military expenditures(开支) or did not pay any taxes will benefit from the protection afforded.

    It is no easy task to determine the social costs and social benefits associated with a public good．There is no practicable way of charging drivers for looking at highway signs,  sailors for watching a lighthouse, and citizens for the security provided to them through national defense．Because the market does not provide the necessary signals, economic analysis has to be substituted for the impersonal judgment of the marketplace.

1．With what topic is the passage mainly concerned?

A．Mechanisms for safer navigation.

B．The economic structural of the marketplace.

C．A specific group of commodities.

D．The advantages of lowering taxes.

2．Which of the following would NOT be an example of a public good as described in the passage?

A．A restaurant.

B．A road sign.

C．A bridge.

D．A stoplight.

3．By which of the following could the word “holds”(in Paragraph 2)best be replaced?

A．has

B．grasps

C．remains

D．carries

4．According to the passage, finding out the social costs of a public good is a ________

A．difficult task.

B．daily administrative duty.

C．matter of personal judgment.

D．citizen’s responsibility.

5．Which of the following statements best describes the organization of the first two paragraphs?

A．Suggestions for the application of an economic concept are offered.

B．Several generalizations are presented from which various conclusions are drawn.

C．Persuasive language is used to argue against a popular idea.

D．A general concept is defined and then examples are given.

中国在96年展开了一场公共广告服务的运动，从那时候起，大量的公益广告在全国涌现。

China began a nationwide public service advertising campaign in 1996, and_______ ________ numerous PSAs have appeared around the country.

北京每月22日定为“让座日”，在公交车上经常让座的乘客，将有机会获得奖励。对此，网民看法不一。请根据下表所提供的信息，写一篇100字左右的短文，谈谈你自己的看法。