TEXT C
　　There must be few questions on which responsible opinion is so utterly divided a s on that of how much sleep we ought to have. There are some who think we can le ave the body to regulate these matters for itself. "The answer is easy," says Dr . A. Burton. "With the right amount of sleep you should wake up fresh and alert five minutes before the alarm rings." If he is right many people must be undersl eeping, including myself. But we must remember that some people have a greater i nertia than others.This is not meant rudely. They switch on slowly, and they a re reluctant to switch off. They are alert at bedtime and sleepy when it is time to get up, and this may have nothing to do with how fatigued their bodies are, or how much sleep they must take to lose their fatigue.
　　Other people feel sure that the present trend is towards too little sleep. To qu ote one medical opinion, thousands of people drift through life suffering from the effects of too little sleep; the reason is not that they can't sleep. Like a dvancing colonists, we do seem to be grasping ever more of the land of sleep for our waking needs, pushing the boundary back and reaching, apparently, for a poi nt in our evolution where we will sleep no more. This in itself, of course, need not be a bad thing. What could be disastrous, however, is that we should press too quickly towards this goal, sacrificing sleep only to gain more time in which to jeopardize our civilization by actions and decisions made weak by fatigue. Then, to complete the picture, there are those who believe that most people are persuaded to sleep too much. Dr H. Roberts, writing in Every Man in Health, asse rts: "It may safely be stated that, just as the majority eat too much, so the ma jority sleep too much." One can see the point of this also. It would be a pity t o retard our development by holding back those people who are gifted enough to w ork and play well with less than the average amount of sleep, if indeed it does them no harm. If one of the trends of evolution is that more of the life span i s to be spent in gainful waking activity, then surely these people are in the va n of this advance.
　　74. The author seems to indicate that___.
　　 are many controversial issues like the right amount of sleep
　　 many issues the right amount of sleep is the least controversial
　　 are now moving towards solving many controversial issues
　　 right amount of sleep is a topic of much controversy among doctors
　　75.The author disagrees with Dr. Burton because___.
　　 people can wake up feeling fresh and alert
　　 people still feel tired with enough sleep
　　 people still feel sleepy with enough sleep
　　 people go to bed very late at night
　　76.In the last paragraph the author points out that___.
　　ng less is good for human development
　　 ought to be persuaded to sleep less than before
　　 is incorrect to say that people sleep too little
　　 who can sleep less should be encouraged
　　77. We learn from the passage that the author___.
　　ts on three different opinions
　　s one of the three opinions
　　ns an opinion of his own
　　s someone else's opinion
　
TEXT D
　　Migration is usually defined as "permanent or semipermanent change of residence. " This broad definition, of course, would include a move across the street or ac ross a city. Our concern is with movement between nations, not with internal mig ration within nations, although such movements often exceed international moveme nts in volume. Today, the motives of people who move short distances are very si milar 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 ass ociated with the place of origin. A push factor can be as simple and mild a matt er as difficulty in finding a suitable job. or as traumatic as war, or severe fa mine. Obviously, refugees who leave their homes with guns pointed at their heads are motivated almost entirely by push factors (although pull factors do influen ce their choice of destination).
　　Pull factors are those associated with the place of destination. Most often thes e are economic，such as better job opportunities or the availability of good lan d to farm. The latter was an important factor in attracting settlers to the Unit ed States during the 19th century. In general, pull factors add up to an apparen tly 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 de stinations, the deciding factor might be a non-economic consideration such as th e presence of relatives, friends, or at least fellow countrymen already establis hed in the new place who are willing to help the newcomers settle in. Considerat ions of this sort cad to the development of migration flow.
　　Besides push and pull actors, there are what the sociologists call "intervening obstacles" Even if push and(or) pull factors are very strong they still may be ou tweighed 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 problem s likely to be encountered on arrival.The decision to move is also influenced by "personal factors" of the potential m igrant. The same push-pull factors and obstacles operate differently on differen t people, sometimes because they are at different stages of their lives, or just because of their varying abilities and personalities. The prospect of packing u p 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 lear n a new language and customs may excite one person and frighten another. Regardless of why people move, migration of large numbers of people causes confl ict. The United States and other western countries have experienced adjustment p roblems with each new wave of immigrants. The newest arrivals are usually given the lowest-paid jobs and are resented by native people who may have to compete w ith them for those jobs. It has usually taken several decades for each group to be accepted into the mainstream of society in the host country.
　　78. The author thinks that pull factors___.
　　 all related to economic considerations
　　 not as decisive as push factors
　　e a range of considerations
　　 more important than push factors
　　79. People's decisions to migrate might be influenced by all the follow ing EXC EPT___.
　　alities.
　　ion.
　　l status.
　　ies.
　　80. The purpose of the passage is to discuss___.
　　 problems of international migrants
　　 motives of international migrants
　　ion inside the country
　　ion between countries