The（72)has several major components, including the system kernel, a memory management syst

system, the file system manager, device drivers, and the system libraries.

（72）

A. application

B. information system

C. operating system

D. iterative

like RIP, treats eaCh network as equals.The (71) of passing through eaCh network is the same;it is one (72) Count.So if a paCket passes through 10 network to reaCh the Destination, the total Cost is 10 hop Counts.Other protoCols, suCh as OSPF, allow the aDministrator to assign a Cost for passing through a network BaseD on the type of serviCe requireD.A (73) through a network Can have Different Costs(metriCs).For example, if maximum (74) is the DesireD type of serviCe, a satellite link has a lower metriC than a fiBer-optiC line.On the other hanD, if minimum (75) is the DesireD type of serviCe, a fiBer-optiC line has a lower metriC than a satellite line.OSPF allow eaCh router to have several routing taBle BaseD on the requireD type of serviCe.

（71）

A．numBer

B．ConneCtion

C．Diagram

D．Cost

cess (program-to-program) communication; TCP uses port (71) to accomplish this. Another responsibility of a transport layer protocol is to create a (72) and error-control mechanism at the transport level. TCP uses a sliding (73) protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve (74) control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends (75) of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

（71）

A．numbers

B．connections

C．diagrams

D．resources

听力原文：W: How are you getting on with your experiment？

M: In spite of my continuous failure, I have already made some progress.

What can we learn about the man's enperiment ？

A．It is going on well.

B．It has failed several times.

C．It will soon be finished.

D．It may have to be stopped.

rocess (program-to-program) communication; TCP uses port （71） to accomplish this. Another responsibility of a transport layer protocol is to create a （72） and error-control mechanism at the transport level. TCP uses a sliding （73） protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve （74） control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends （75） of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

（71）

A. numbers

B. connections

C. diagrams

D. resources

（72）

A. procedure

B. function

C. route

D. flow

（73）

A. path

B. window

C. frame

D. diagram

（74）

A. packet

B. time

C. error

D. phase

（75）

A. ports

B. streams

C. packets

D. cells

l, like RIP, treats each network as equals. The （71） of passing through each network is the same; it is one （72） count. So if a packet passes through 10 network to reach the destination, the total cost is 10 hop counts. Other protocols, such as OSPF, allow the administrator to assign a cost for passing through a network based on the type of service required. A （73） through a network can have different costs (metrics). For example, if maximum （74） is the desired type of service, a satellite link has a lower metric than a fiber-optic line. On the other hand, if minimum （75） is the desired type of service, a fiber-optic line has a lower metric than a satellite line. OSPF allow each router to have several routing table based on the required type of service.

（71）

A. number

B. connection

C. diagram

D. cost

（72）

A. process

B. hop

C. route

D. flow

（73）

A. flow

B. window

C. route

D. cost

（74）

A. packet

B. throughput

C. error

D. number

（75）

A. delay

B. stream

C. packet

D. cost

ess-to-process communication; UDP uses （71） numbers to accomplish this. Another responsibility is to provide control mechanisms at the transport level. UDP does this task at a very minimal level. There is no flow control mechanism and there is no （72） for received packet. UDP,however, does provide error control to some extent. If UDP detects an error in the received packet, it will silently drop it．

The transport layer also provides a connection mechanism for the processes. The （73） must be able to send streams of data to the transport layer. It is the responsibility of the transport layer at （74） station to make the connection with the receiver, chop the stream into transportable units,number them, and send them one by one. It is the responsibility of the transport layer at the receiving end to wait until all the different units belonging to the same process have arrived, check and pass those that are （75） free, and deliver them to the receiving process as a stream.

（71）A．hop B．port C．route D．packet

（72）A．connection B．window C．acknowledgement D．destination

（73）A．jobs B．processes C．programs D．users

（74）A．sending B．routing C．switching D．receiving

（75）A．call B．state C．cost D．error

rialized countries. The current annual marriage【21】in the United States—about 9 new marriages for every 1,000 people—is【22】higher than it is in other industrialized countries. However, marriage is【23】as widespread as it was several decades ago.【24】of American adults who are married【25】from 72 percent in 1970 to 60 percent in 2002. This does not mean that large numbers of people will remain unmarried【26】their lives. Throughout the 20th century, about 90 percent of Americans married at some【27】in their lives. Experts【28】that about the same proportion of today's young adults will eventually marry.

The timing of marriage has varied【29】over the past century. In 1995 the average age of women in the United States at the【30】of their first marriage was 25. The average age of men was about 27. Men and women in the United States marry【31】the first time at an average of five years later than people【32】in the 1950s.【33】, young adults of the 1950s married younger than did any previous【34】in U. S. history. Today's later age of marriage is【35】the age of marriage between 1890 and 1940.【36】, a greater proportion of the population was married (95 percent) during the 1950s than at any time before【37】. Experts do not agree on【38】the "marriage rush" of the late 1940s and 1950s occurred, but most social scientists believe it represented a【39】to the return of peaceful life and prosperity after 15 years of severe economic【40】and war.

(1)

A．ratio

B．rate

C．percentage

D．poll

ir intention to proceed to monetary union among the non-CFA franc countries of the region by January 2003, as a first step toward a wider monetary union including all the ECOWAS countries in 2004. The six countries【71】themselves to reducing central bank financing of budget deficits【72】10 percent of the previous year's government【73】; reducing budget deficits to 4 percent of the second phase by 2003; creating a Convergence Council to help【74】macroeconomic policies; and【75】up a common central bank. Their declaration【76】that, "Member States【77】the need【78】strong political commitment and【79】to【80】all such national policies【81】would facilitate the regional monetary integration process.

The goal of a monetary union in ECOWAS has long been an objective of the organization, going back to its formation in 1975, and is intended to【82】a broader integration process that would include enhanced regional trade and【83】institutions. In the colonial period, currency boards linked sets of countries in the region.【84】independence,【85】, these currency boards were【86】, with the【87】of the CFA franc zone, which included the francophone countries of the region. Although there have been attempts to advance file agenda of ECOWAS monetary cooperation, political problems and other economic priorities in several of the region's countries have to【88】inhibited progress. Although some problems remain, the recent initiative has been bolstered by the election in 1999 of a democratic government and a leader who is committed to regional【89】in Nigeria, the largest economy of the region, raising hopes that the long-delayed project can be【90】.

(41)

A．committed

B．devoted

C．adjusted

D．attributed

Man cannot go on increasing his number at the present rate. In the (56) 30 years man will face a period of crisis. (57) experts believe that there will be a widespread food (58) Other experts think this is (59) pessimistic (悲观的), and that man can prevent things from (60) worse than they are now. But remember that two thirds of the people in the world are under-nourished or starving now.

(61) thing that man can do is to limit the (62) of babies born. The need (63) this is obvious, but it is not (64) to achieve. People have to be 65 to limit their families. In the countries of the population (66) , many people like big families. The parents think that this (67) a bigger income for the family and ensures there will be someone in the family who will look (68) them in old age.

Several governments have (69) birth control policies in recent years. (70) them are Japan, China, India and Egypt. In some (71) the results have not been successful. Japan has been an (72) . The Japanese adopted a birth control policy in 1948. People were (73) to limit their families. The birth (74) fell from 34. 3 per thousand per year to about 17. 0 per year (75) present.

(61)

A．second

B．recent

C．next

D．late