1. Passage Twenty-FourSocial change is more likely to occur in societies where there is a mixture of different kinds of people than in societies where people are similar in many ways.The simple reason for this is that there are more different ways of looking at things present in the first kind of society.There are more ideas， more disagreements in interest， and more groups and organizations with different beliefs.In addition， there is usually a greater worldly interest and greater tolerance in mixed societies.All these factors tend to promote social change by opening more areas of life to decision.In a society where people are quite similar in many ways， there are fewer occasions for people to see the need or the opportunity for change because everything seems to be the same.And although conditions may not be satisfactory， they are at least customary and undisputed.Within a society， social changes is also likely to occur more frequently and more readily in the material aspects of the culture than in the non-material， for example， in technology rather than in values; in what has been learned later in life rather than what was learned early; in the less basic and less emotional aspects of society than in their opposites; in the simple elements rather than in the complex ones; in form rather than in substance; and in elements that are acceptable to the culture rather than in strange elements.Furthermore， social change is easier if it is gradual.For example， it comes more readily in human relations on a continuous scale rather than one with sharp dichotomies (一分为二).This is one reason why change has not come more quickly to Black American as compared to other American minorities， because of the sharp difference in “appearance between them and their white counterparts”.The passage has mainly discussed ().

49.After( )the numbers＇ in every possible combination， we finally hit on a solution.

A. 　running through

B. 　running after

C. 　running over

D. 　running out

42.This medicine contains some chemicals that may negatively affect your health.

13.I hope all the precautions against air pollution， ()suggested by the local government， will be seriously considered here.

A. 　while

B. 　since

C. 　after

D. 　as

1I.Tony is very disappointed ()the results of the exam.

A. 　with

B. 　for

C. 　toward

D. 　on

40. Questions 36 to 40 are based on the following passage.Some people have said aging is more a slide into forgetfulness than a journey towards wisdom.However， a growing body of research suggests that late-in-life learning is possible.In reality， education does an aging brain good.Throughout life， people’s brains constantly renovate themselves.In the late 1960s， British brain scientist Geoffrey Raisman spied growth in damaged brain regions of rats through an electron microscope; their brains were forging new connections.This meant brains may change every time a person learns something new.Of course， that doesn’t mean the brain isn’t affected by the effects of time.Just as height usually declines over the years， so does brain volume: Humans lose about 4 percent every decade starting in their 40s.But that reduction doesn’t necessarily make people think slower; as long as we are alive and functioning， we can alter our brains with new information and experiences.In fact， scientists now suspect accumulating novel experiences， facts， and skills can keep people’s minds more flexible.New pathways can strengthen our ever-changing mental structure， even as the brain shrinks.Conventional fixes like word puzzles and brain-training apps can contribute to mental durability.Even something as simple as taking a different route to the grocery store or going somewhere new on vacation can keep the brain healthy.A desire for new life challenges can further boost brainpower.Research about aging adults who take on new enterprises shows improved function and memory as well as a reduced risk of mental disease.Openness—a characteristic defined by curiosity and a desire for knowledge—may also help folks pass brain tests.Some folks are born with this take-in-the world attitude， but those who aren’t as genetically gifted aren’t necessarily out of luck.While genes can encourage an interest in doing new things， a 2012 study in the journal Psychology and Aging found completing reasoning tasks like puzzles and number games can enhance that desire for novel experiences， which can， in turn， refresh the brain.That’s why brain scientist Richard Kennedy says “It’s not that old dogs can’t learn new tricks.It’s that maybe old dogs don’t realize why they should.”What is the finding of the 2012 study in the journal Psychology and Aging?

A. 　Wishing to solve puzzles enhances one’s reasoning power.

B. 　Playing number games unexpectedly stimulates one’s memory.

C. 　Desiring new experiences can help to renovate the brain.

D. 　Learning new tricks should not be confined to old dogs only.

1. Passage Thirty-FourMuch unfriendly feeling towards computers has been based on the fear of widespread unemployment resulting from their introduction.Computers are often used as part of automated (自动化的)production systems requiring a least possible number of operators， causing the loss of many jobs.This has happened， for example， in many steelworks.On the other hand， computers do create jobs.They are more skilled and better paid， though fewer in number than those they replace.Many activities could not continue in their present form without computers， no matter how many people are employed.Examples are the check clearing (交换)system of major banks and the weather forecasting system.When a firm introduces computers， a few people are usually employed in key posts (such as jobs of operations managers)while other staff are re-trained as operators， programmers， and data preparation staff.After the new system has settled down， people in non-computer jobs are not always replaced when they leave， resulting in a decrease in the number of employees.This decrease is sometimes balanced by a substantial increase in the activity of the firm， resulting from the introduction of computers.The attitudes of workers towards computers vary.There is fear of widespread unemployment and of the takeover of many jobs by computer-trained workers， making promotion for older workers not skilled in computers more difficult.On the other hand， many workers regard the trend toward wider use of computers inevitable.They realize that computers bring about greater efficiency and productivity， which will improve the condition of the whole economy， and lead to the creation of more jobs.This view was supported by the former British Prime Minister， James Callaghan in 1954， when he made the point that new technologies hold the key to increased productivity， which will benefit the economy in the long run.The unfriendly feeling towards computers is developed from ().

20.Some women ()a good salary in a job instead of staying home， but they decided not to work for the sake of the family.

A. 　must make

B. 　should have made

C. 　would make

D. 　could have made

45.After being tested in many ways， this newly-designed machine will ()in the near future.

A. 　take place

B. 　put into use

C. 　come into use

D. 　take action

4. Passage ElevenDoctors say anger can be an extremely damaging emotion， unless you learn how to deal with it.They warn that anger can lead to heart disease， stomach problems， headaches， emotional problems and breast cancer.Anger is a normal emotion that we all feel from time to time.Some people express anger openly in a calm and reasonable way.Others burst with anger， screaming and yelling.But still others keep their anger inside.They cannot or will not express it.This is called (repressing)anger.For years some doctors claim that both repressing and expressing anger can be dangerous.They say that in both situations the brain of an angry person releases the same hormones (荷尔蒙).They spend the heart rate， raise blood pressure or sugar level in the blood.As a result， the angry person feels excited and is ready to react.The violent reaction may lead to high blood pressure.However， some other doctors argue that repressing anger is more dangerous to a person’s health than expressing it.They believe that those who keep their anger inside may face a greater danger of heart disease.Most doctors agree that it is important to learn how to deal with anger.They say the first step is to admit that you are angry and recognize the real cause of the anger， then decide if the cause is serious enough to get angry about.If so， you should not express your anger immediately and try to wait until your anger has cooled down， so that you are able to express yourself calmly and reasonably.They also believe that a good way to deal with anger is to find humor in the situation that has made you angry.After all， it is much healthier to laugh than to get angry.What is the best title for this passage?

1. Passage Twenty-SixToday just as technology changed the face of industry， farmers have undergone an “agricultural revolution”.On the farm of today， machines provide all the power.One of the most important benefits will be the farm computer.A few forward-looking farmers are already using computers to help them run their farms more efficiently.The computers help them keep more accurate records， so they can make better decisions on what crops to plant， how much livestock to buy， when to sell their products， and how much profit they can expect.Many computer companies have been developing special computer programs just for farmers.Programs are being written for hog (猪)producers， grain farmers， potato farmers， and dairy farmers.In the future， farmers will be able to purchase computer programs made to their needs.Because of the growing importance of computers on the farm， students at agricultural colleges are required to take computer classes in addition to their normal agricultural courses.There can be no doubt that farmers will rely on computers even more in the future.While the old-time farm depended on horse power， and modern farms depend on machine power， farms of the future will depend on computer power.Another technological advance which is still in the experimental stage is the robot， a real “mechanized hired hand” that will be able to move and， in some ways， think like a human being.Agricultural engineers believe that computer-aided robots will make startling changes in farming before the end of the century.Unlike farmers of the present， farmers of the future will find that many day-to-day tasks will be done for them.Scientists are now developing robots that will be able to shear (修剪)sheep， drive tractors， and harvest fruit.Even complex jobs will be done by robots.For example， in order to milk their cows， farmers must first drive them into the special barn (畜棚)， then connect them to the milking machines， watch the machines， and disconnect them when they are finished.In the future， this will all be done by robots.In addition， when the milking is completed， the robots will automatically check to make sure that the milk is pure.The complete mobilization of the farm is far in the future， but engineers expect that some robots will be used before long.Which sentence is the main idea of the whole passage?