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Unit 1，There are two factors which determine an individuals intelligence.The first is the sort of brain he is born with.Human brains differ considerably, some being more capable than others.But no matter how good a brain he has to begin with ,an individual will have a low order of intelligence unle he has opportunities to learn.So the second factor is what happens to the individual-the sort of environment in which he is brought up.If an individual is handicapped environmentally, it is likely that his brain will fail to develop and he will never attain the level of，intelligence of which he is capable.The importance of environment in determining an individuals intelligence can be demonstrated by the case history of the identical twins, Peter and John.When the twins were three months old, their parents died, and they were placed in separate foster homes.Peter was reared by parents of low intelligence in an isolated community with poor educational opportunities.John, however, was educated in home of well-to-do parents who had been to college, This environmental difference continued until the twins were in their late teens, when they were，given tests to measure their intelligence.Johns I.Q was 125,twenty-five points higher than the average and fully forty points higher than his identical brother.Unit 2
Recent studies of the human brain have resulted in some interesting discoveries.Scientists believe that a way to improve the power of the brain may soon be poible.Scientists have discovered that the brain can make its own drugs.The brain contains a protein substance which can act directly on the brain to change aspects of mental activity.Some may change or improve, for example, creativity, intelligence, imagination, and good memory.Chemicals found in the brain carry meages.In recent years scientists have found chemicals that affect mood, memory and other happenings of the mind.About 25 have been found so far.Today the role of chemicals and protein substance in human behaviour is creating much interest.Research seems to show that they may help control insomnia, pain, and mental illne.They have a great capacity to stimulate the brain to conquer deficiencies.They also improve the qualities of memory and learning already in the brain.They hold the secret to mood and emotion.Some day there may be a chemical way to create a better more efficient brain.Unit 3，By measuring the amount of HIVs genetic material in various representative tiue samples from infected people, and extrapolating form these samples to the entire body, Haase estimates that at most 1 in 2,500 cells, maybe fewer, is infected with HIV.This is nowhere near enough for direct cell killing to account for the depletion in their numbers that leads to AIDS.Haase says that his own work now shows that large numbers of CD4 cell ate becoming trapped in lymph tiue, and he believes that HIV also disrupts the production of new cells.In common with a number of other researchers, he also believes that HIV may cause the lo of uninfected CD4 cells by triggering abnormally high levels of cell suicide ,or apoptosis-a separate proce that has been a subject of research throughout the 1990s.Taken together, these findings clearly suggest that HIV keeps the immune system in a state of constant activation, and unbalances it in four ways :by trapping mature cells ,by stopping the production of new cells, by triggering abnormally high rates of apoptosis and by killing a small but significant number of cells directly.Their combined impact leaves the immune system depleted and unable to cope with opportunistic infections.How will any of this affect treatments? Would better knowledge of the ways in which the virus disturbs the immune system enable researchers to rebuild it ,broadening the depleted repertoire of CD4 cells ? Roederer , at least, thinks that drugs that directly affect the immune system will be needed.Others go further, Jay Levy at the University of California , San Francisco, worries that prolonged treatment with cocktails of antiviral drugsmight even fool the immune system and “put it to rest”, by keeping levels of HIV so low in the body that they fail to trigger any immune responses at all.This might make individuals who stop taking the drugs even more vulnerable.He argues that immune-restoring treatments should be given alongside antiviral drugs.Already, some researchers are working on novel approaches such as developing genetically engineered T cell to replace lose CD4 cells.Unit 4what is Golbalization?
Economic “globalization” is a historical proce, the result of human innovation and technological progre.It refers to the increasing integration of economies around the world , particularly through trade and financial flows.The term sometimes also refers to the movement of
people(labor)and knowledge(technology)acro international borders.There are also broader cultural, political and environmental dimensions of globalization that are not covered here.At its most basic, there is nothing mysterious about globalization.The term has come to common usage since the 1980s, reflecting technological advances that make it easier and quicker to complete international transactions –both trade an financial flows, It refers to an extension beyond national borders of the same market forces that have operated for centuries at all levels of human economic activity-village markets, urban industries ,or financial centers.Markets promote efficiency through competition and the division of labor-the specialization that allows people and economies to focus on what they do best.Global markets offer greater opportunity for people to tap into more and larger markets around the world.It means that they can have acce to more capital flows, technology, cheaper imports, and larger export markets.But markets do not necearily ensure that the benefits of increased efficiency are shared by all.Countries must be prepared to embrace the policies needed, and in the case of the poorest countries may need the support of the international community as they do so.
