北美托福机经英文版原文(1)

　　1. 关于STREAM 的文章。
　　第一段，streams 里的 sediments。
　　说河流里改变landscape，主要通过erosion而不是weathering。
　　这里有一道题是关于streams怎样影响landscape。
　　第二段，streams里的sediments有三种形式。
　　第三段，第一种是溶解在河水里了，然后河水流到哪里就带着它去哪里。
　　第四段，好像是讲一些小部分没有溶解在水里的sediments，具体记不清楚了。
　　第五段，讲在河床上较大块的sediments。说这些平常都不怎么动，在经历大洪水的时候会被移动，所以很难被观测。
　　2. native Canadian
　　开始讲好多原始的资料都没有得到很好的保存。欧洲人跑到加拿大后，那些资料都变得fragmented， 然后时间顺序也搞混了。讲到native people 怎样记录他们的生活和文化，都是由男人写，被隔离起来，所以这些记录都是建立在这些写的人的基础上，然后也限制去探望的人。所以欧洲人去了以后也搞不清楚，因为即使他们在那里住很长时间，也不会有机会去了解。
　　然后说欧洲的native的影响在欧洲人没去加拿大的时候就有了，因为native people使用很多goods都是欧洲产的。欧洲人到了以后都是在春天到秋天的这段时间搞农业，还讲到了水资源，说道欧洲人搞了map都是根据河流资讯的，还搞了个什么东西。Native people会迁移，根据不同的季节travel very long distance。
　　最后一段讲欧洲人记录的native people的生活和文化也不是非常准确。最开始他们用画画的方式记录，但是这些都会收到个人想法的影响。即使后来用了照相机，也还是不怎么准确，因为个人想法，角度还是影响这些记录。
　　2. 学者研究北美居民的本来生活是比较困难的。因为据研究表明，很多native居民在真正接触newcomer之前就已经在使用欧洲的goods 或者技术。大部分移民最初目的是要找资源。影响因素还有很多移民探险的人长时间跟本地居民居住生活；这些新移民和自己国家和亲人隔离太久。
　　3. 原始人作画用什么工具
　　第一段讲开始对原始艺术的理解有偏差，好像原来怀疑这些玩意儿都是God 或者神灵创作的。后来就一直这些原始的艺术品是用一种石头工具制作的。然后给出几个例子。后来提到了用了现代技术，chemical还有显微镜之类的。
　　4. 鸟的迁徙，途中经过撒哈拉沙漠和地中海，它们怎么完成这么长的距离。
　　新托福真题题源：Birds face longer migration due to climate change, experts warn
　　Migrating birds such as the garden warbler and whitethroat will face longer journeys because of climate change, experts warned today.
　　A team of scientists led by Durham University has demonstrated that while the birds' breeding ranges are likely to shift northwards, their wintering areas will not, thus increasing the length of their journeys by up to 250 miles. The study, published in the Journal of Biogeography, has serious implications for many of the birds returning this month to Britain to breed.
　　The research team used computer simulation models similar to those used by weather forecasters to analyse how climate change might affect the migration patterns of European Sylvia warblers.
　　Every year these tiny birds – some weighing as little as 12g – travel thousands of miles northwards from their African winter-quarters to breed in Europe and Asia. Up to 500 million birds undertake this epic journey to take advantage of the long summer days and glut of insect food in temperate latitudes.
　　But as climate change leads to rises in spring and summer temperatures, some of these long-distance migrants are responding by shifting their breeding ranges further north, making their return journey each spring even longer than before. In future, when they return to Africa in autumn, the predicted southward extension of the Sahara Desert may also eventually increase their travel distance.
　　Dr Stephen Willis of Durham University, who co-ordinated the study, stressed the problems this additional mileage will pose. "From 2071 to 2100, nine out of the 17 species we looked at are projected to face longer migrations, particularly birds that cross the Sahara desert. The added distance is a considerable threat," he said.
　　Different birds follow different migration strategies, with some species covering the distance in short hops. Others, such as the sedge warbler, fatten up and almost double their body weight before making the journey across the Sahara and Mediterranean Sea in a single leap. But whichever way they travel, longer journeys will make enormous demands on their energy resources, which they may not be able to meet.
　　Professor Rhys Green of the RSPB, who co-authored the research paper, believes that this increase in distance – though relatively small compared with the total journey the birds undertake – is likely to cause major problems. "Anything that makes those journeys longer or more dependent on vulnerable pit-stop habitats used for refuelling on migration could mean the difference between life and death," he warned.
　　There is evidence that short-term climatic effects have caused problems in the past. For example, the prolonged drought in the Sahel Zone of western Africa during the late 1960s led to a massive 90% fall in the British population of whitethroats in a single year, from 1968 to 1969. Although numbers later recovered, the species remains highly vulnerable to sudden environmental change.
　　Some species, however, may already be beginning to adapt their migration patterns as a result of climate change. The chiffchaff, which normally migrates to Iberia and North Africa rather than crossing the Sahara, now regularly overwinters in Britain, especially in the milder areas of the south and west. Meanwhile the German and Austrian populations of the blackcap, one of the species followed in the study, now migrate west instead of south to spend the winter here in the UK.
　　If other species can follow suit by changing their migration patterns they may be able to survive. "Some species may be able to adapt and change, for example by adopting shorter migration routes, if they can find enough food at the right time," said Willis.
　　"Bird migrations are incredible feats of stamina and endurance but, as temperatures rise and habitats change, birds will face their biggest challenge since the Pleistocene era."
　　5. 板块漂移学说。板块漂移学说提出之前，大家都认为地壳都是垂直运动。等到此学说提出后，很多边缘学者承认，但是主流学者不承认，他们认为提出者只依靠了化石材料，并没有说明物种差别。很多年后，新的证据被发现，才流行开来。
　　辞汇题：constitute = make up；eventually = at the end