山东行政学院的专科证书能否报考成人高考专升本？

坚持马克思主义哲学的认识路线，就必须在工作中坚持

A.一切从实际出发
B.—切从主观的愿望出发
C.一切从理论出发
D.—切从臆造的规律出发

A.ex+C
B.ex+2x+C
C.ex+x2+C
D.(ex+2)2+C

毛泽东第一次正式地提出“人民民主专政”的概念是在（ ）

A.《将革命进行到底》
B.《论人民民主专政》
C.《共同纲领》
D.《中国革命和中国共产党》

Public goods are those commodities from whose enjoyment nobody can be effectively excluded.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 is a public?goods.Once the dam is built,all persons living in the area will benefit--irrespective of their own?contribution to the construction cost of the dam.The same holds tree for highway signs or aids to navigation.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 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 public goods.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?judgement of the marketplace.

Which of the following would NOT be an example of public goods as described in the passage?

A.A taxi.
B.A bridge.
C.A fire truck.
D.A stoplight.