听力原文：

　　Why should mankind explore space? Why should money, time and effort be spent in exploring, investigating and researching something with so few benefits? Why should resources be spent on space rather than on conditions and people on earth or in our own country? Perhaps the best answer lies in our genetic make-up. What drove our distant ancestors to move from the trees onto the plains? Was it the lack of skills to compete in one ecological niche? If so the adaptation selected for after the move have resulted in the species expanding into all possible areas and environment，the drive to spread genetic material and ensure the success of not just the species but of one type of genetic material. The wider the distribution of a species, the better the chance of survival. Perhaps the best reason for exploring space is the built-in genetic predisposition to expand into all possible niches. Culturally nearly every successful civilization has been willing to explore. In exploring, dangers of surrounding areas may be learned and prepared for. Dangers may be political enemies in neighboring cultures, physical features of the area, a change in the area which might affect food supplies or any other number of factors. All pose a real danger and all may be made less dangerous if certain preparations are made. Without knowledge, the danger may strike and completely destroy, with knowledge, the effects or consequences may be lessened. Exploration also allows resources to be located. Resources translate into power and success at survival. Whether the success be financial, political or genetic additional resources are always a boon when used wisely. In any of the three manners, use of resources allows a heightened percentage for survival. If the resources have no immediate need, then perhaps later the resources will be used. Resources may be more than physical assets. Knowledge or techniques acquired in exploring or preparing to explore always filter from the developers to the general populace. Techniques may be medical applications, uses for drugs or ways of living to increase the quantity of time lived or the quality of that time. Techniques may be social, allowing the people in a society to better understand those within or outside the culture. Better understanding may lead to better use of resources or a lessening of outright competition for the resources.

　　While many resources are spent on what seems a small return, the exploration of space allows the creative, the brave, the intelligence of our species to focus on that may serve to save us. While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. The chance of a large asteroid or comet hitting he earth is small. But given time, it will happen. Several current models of evolution propose many changes in a very short time period. Some explanations for the drastic speed of extinction and evolution include strikes by asteroids or comets. Human technology is reaching the point where it might be able to detect such a threat and allow us to do something about it. The danger exists, but knowledge can allow us as a species to survive. Without the ability to reach out across space, the chance to save ourselves might not exist. While earth is the only planet known to sustain life, surely the adaptive ability of humans would allow other planets and moons to become inhabited. True the life style would be different, but human life and cultures have adapted in the past and surely could in the future. Our genetic make-up will allow humans to move into unoccupied niches and flourish. The culture group holding the high ground has attained a great advantage over outer groups. It can see farther, act sooner and be safer from attack. In space all of these things are true. The culture which expands is like and organism which adapts. It may be found everywhere. If one group is eliminated, the species as a whole survives. The old adage, do not put all your eggs in one basket holds true for humans and cultures. The more a culture expands, the less chance of it becoming extinct. Space allows us to expand and succeed.

　　这篇科普文章其实解答了很多人心中一直以来的一个困惑：我们为什么要去探索外太空?同样的人力物力，如果花费在改善人们的生活状况上，收益会比投入到外太空立竿见影得多。最佳答案可能就存在于我们的基因组成上，换句话说，我们天性使然。老祖先们从树上来到了平地上，也是为了开拓一片新的天地。“The wider the distribution of a species, the better the chance of survival.” 物种扩散的越广，存活的几率就越大。

　　文章很长而且不简单，比较容易走神。有些词又确实构成了难度，比如“ecological niche” 生态小生境、“built-in genetic predisposition”内在天性、“heightened percentage”提高了的百分比、“asteroid or comet”小行星或彗星、“general populace”普罗大众、“adage” 格言谚语(其实从后文“do not put all your eggs in one basket”猜出空格要填的意思，如写上saying或proverb也可以)。

　　1. In the early 1990s, some influential people said that being in single-sex classes could raise a girl’s self-esteem. Schools across the country began creating single-sex classrooms and schools. But many critics claim that all female schools may actually be detrimental to a girl’s education, because they reinforce the regressive notion of sex differences. The renewed interest in single-sex schooling has fostered a controversy among Americans. Those who give it full endorsement believe girls need an all-female environment to take risks and find their own voices. Those who question the validity of single-sex schooling believe there is no such thing as separate but equal.

　　这篇的主题是“single-sex school”---单性别学校(在此特指女校)，文章是有难度的。前两句讲的是上世纪90年代初期兴起的女校热潮。第三句从首字“But”的转折中，可以预期与之前两句的对立。虽然形容词“detrimental”稍有难度，但是从这个对立的角度，可以猜出是“有害的”或“不利的”意思。之后马上又出现“because”引出“有害”的原因， “reinforce the regressive notion”可以判断出是“强调了这种落后观念”。后一句提到当今美国，单性别学校又卷土重来。之后那句的主语“Those who give it full endorsement”就应该承接上文，表示“支持这种教育方式的人”。最后一句的主语“Those who question the validity of single-sex schooling”，凭借动词“question”就知道是“反对者、质疑者”。

　　2. Now I'd like to identify some key changes in our cities. First of all, they're getting bigger and bigger. For the first time in history, there will soon be more people living in urban areas than in rural environments. In 1950, New York City was the only city with a population of 10 million. Now, in 2010, worldwide we have 38 cities with populations of over 10 million people--what we call megacities. Cities are also getting taller because land is getting more and more expensive. We can have a tall apartment building that a thousand people can live in. Skyscrapers have become a symbol of modern cities.

　　与第一篇比较，这篇就显得相对简单。从首句“identify some key changes”中的“some”，就可以预期接下去的行文中会出现几点。课上重点讲过，首句有“some”“several”“a number of”之类的提示词，下文要做好记录“一二三”的准备。

　　本文就讲了两点：城市越变越大，同时越来越高。脉络很清楚，但不能掉以轻心，要记录好数字。