Thermosetting plastics are those that do not soften when heated

According to Annex V to MARPOL 73/78，garbage containing plastic is permitted to be disposed of by ______.

A.incinerating offshore

B.discharging when at least 12 nautical miles from nearest land

C.grinding to less than 1 and discharging at least 12 nautical miles from nearest land

D.grinding to less than 1 and discharging at least 25 nautical miles from nearest land

Migration is usually defined as "permanent or semi-permanent change of residence". However, our concern is with movement between nations, not with internal migration within nations, although such movements often exceed international movements in volume. Today, the motives of people who move short distances are very similar to those of international migrants.

Students of human migration speak of "push" and "pull" factors, which influence an individual's decision to move from one place to another. Push factors are associated with the place of origin. A push factor can be as simple and mild a matter as difficulty in finding a suitable job, or as traumatic as war, or severe famine. Obviously, refugees who leave their homes with guns pointed at their heads are motivated almost entirely by push factors (although pull factors do influence their choice of destination).

Pull factors are those associated with the place of destination. Most often these are economic, such as better job opportunities or the availability of good land to farm. In general, pull factors add up to an apparently better chance for a good life and material well-being than is offered by the place of origin. When there is a choice between several attractive potential destinations, the deciding factor might be a non-economic consideration such as the presence of relatives, friends, or at least fellow countrymen already established in the new place who are willing to help the newcomers settle in.

Besides push and pull factors, there are what the sociologists call "intervening obstacles." Even if push and (or) pull factors are very strong they still may be outweighed by intervening obstacles, such as the distance of the move, the trouble and cost of moving, the difficulty of entering the new country, and the problems likely to be encountered on arrival. The decision to move is also influenced by "personal factors" of the potential migrant. The prospect of packing up everything and moving to a new and perhaps very strange environment may appear interesting and challenging to an unmarried young man and appallingly difficult to a slightly older man with a wife and small kids. Similarly, the need to learn a new language and customs may excite one person and frighten another. Regardless of why people move, migration of large numbers of people causes conflict. The United States and other western countries have experienced adjustment problems with each new wave of immigrants. It has usually taken several decades for each group to be accepted into the mainstream of society in the host country.

The author thinks that pull factors ______.

A．are all related to economic considerations

B．are not as decisive as push factors

C．include a variety of considerations

D．are more important than push factors

YouaretheadministratorofaWindows2000network.YouinstallWindows2000ProfessionalonanewcomputerandconfiguretheTCP/IPsettingstohaveastaticIPaddress.Whiletestingnetworkconnectivityfromthenewcomputer,youdiscoveranerrorintheDNSserveraddressthatisconfiguredintheTCP/IPsettings.YouconfigurethecorrectDNSserveraddress,whichis10.1.1.5.However,youarestillunabletosuccessfullyconnecttonetworkresourcesbyname.YouruntheIPconfig/allcommand.TheresultsindicatethattheDNSserveraddressisnowconfiguredas0.0.0.0Youneedtoensurethatthecomputercanconnecttonetworkresourcesbyname.Whatshouldyoudo?（）

Public goods are those products from whose enjoyment nobody can be effectively excluded. Everybody is free to enjoy the benefits of these commodities, and one person’s utilization(利用)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 good. Once the dam is built, all persons living in the area will benefit--regardless of their own contribution to the construction cost of the dam. The same holds true 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 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(代替) for the impersonal judgement of the marketplace.

31. With what topic is the passage mainly concerned?

A. Mechanisms for safer navigation.

B. The economic structure of the marketplace.

C. A specific group of commodities.

D.The advantage of lowering taxes.

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

A.taxi.

B. A bridge.

C. A fire truck.

D. A stoplight.

33. Which of the following can best replace the underlined word “holds”?

A. has

B. is

C. grasps

D. carries

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

A. difficult procedure

B. daily duty

C. matter of personal judgement

D. citizen’s responsibility