老托福20经典听写.docx

1、老托福20经典听写37Weve just seen two contemporary large birds that cannot fly: the emu and the ostrich. Over here is an interesting specimen from the past. This stuffed animal is not the giant penguin it appears to be, but an auk. This particular kind of auk is very rare, only 78 skins are known to exist a

2、nd most are not preserved as well as this one. The great auk, as you can see, was a rather large bird, and it couldnt fly either. However, evidence suggests that the auk was an excellent swimmer and diver. Unfortunately, those abilities did not protect it from being easy prey for hungry sailors who

3、years ago sailed the very cold and often icy waters of Greenland, Iceland, and Scotland. In fact, records indicate that the auk was rather tasty and that its eggs. Excuse me . . . that its eggs and feathers were useful as well. Still, it isnt clear what other factors led to the big birds demise arou

4、nd 1844, the last time anyone reported seeing one. Of course, we believe its important to take extra precautions to preserve the remaining great auk skins. After all, these specimens should prove invaluable for future scientific research. Does anyone have any questions before we move on to our next

5、bird exhibit?【生词摘录】1. contemporary: adj. 当代的，同时代的2. emu: n. C鸸鹋（产于澳洲的一种体型大而不会飞的鸟）3. ostrich: n. C鸵鸟4. specimen: n. C样本；样品；实例5. stuffed: adj. 已经喂饱了的6. penguin: n. C企鹅7. auk: n. C海雀（北极地区海鸟，体大，短翅，蹼足）8. demise: n. U死亡9. precaution: n. C预防，警惕，防范10. invaluable: adj. 无价的，非常宝贵的，价值无法衡量的41Before I tell you ab

6、out the interesting discovery related to Tyrannosaurus rex, I need to review something we studied last semester, the difference between what are commonly called cold-blooded and warm-blooded animals. In warm-blooded animals, birds and mammals, for example, the body temperature normally stays within

7、a narrow range, no matter what the outside temperature is. As a result, a warm-blooded animal is usually active in both cold and hot weather because its body temperature can adjust to the temperature of its environment. On the other hand, cold-blooded animals, such as most reptiles, amphibians, and

8、insects, are unable to create enough heat internally to raise their temperature above the temperature of the environment. So, for example, the temperature of a cold-blooded animal falls when the environment is cool. I hope this distinction is clear. Now, moving on to Tyrannosaurus rex, you may know

9、that dinosaurs, being reptiles, are generally believed to have been cold-blooded. Well, a recent research study found that the chemical composition of the bones of Tyrannosaurus rex was consistent with the bones of an animal that has a very narrow range of internal temperature, indicating that it wa

10、s probably warm-blooded.【生词摘录】1. Tyrannosaurus: 暴龙2. rex: n. C雷克斯猫3. cold-blooded: adj. 冷血的4. warm-blooded: adj. 温血的5. reptile: n. C爬行动物6. amphibian: n.C水路两栖动物7. internally: adv. 在内，内在地8. distinction: n. C区别，差异9. dinosaur: n. C恐龙10. composition: n. C合成物11. consistent: adj. 一致的44This room is devoted

11、to electric fish. The eel in the tank behind me can produce a strong jolt重击 of electricity to stun 打晕its prey, but most of the fish in here produce only weak electrical impulses that are useful for navigating, locating food, and even for communicating. The knife fish is a good example. This fish nav

12、igates, using tiny receptors in the skin that are sensitive to electrical impulses. The knife fish produces an electrical signal, and the receptors in its skin let it know when the signal is distorted by a tree root, or some other obstacle, so it can go around it. Fish also use the ability to produc

13、e and detect electrical impulses to communicate. They can tell each other what species they belong to, how big they are, and whether theyre male or female. We have a tank here thats specially equipped to convert the inaudible signals the fish produce into sounds you can hear when you put on these he

14、adphones. I urge you all to listen in when Im done speaking. Now have a look at the electric rays. Rays are especially interesting to medical researchers because of the organs they use to produce electricity. These organs contain a chemical that carries signals from one nerve ending to the next, not

15、 only in rays, but also in people. By studying these organs, scientists hope to learn more about diseases that interrupt the transmission of impulses from one nerve to another.【生词摘录】1. devote: v. 作标点符号2. eel: n. C鳗（任一种长的蛇形的无鳞海洋或淡水鱼）3. tank: n. C桶，箱，罐，槽，池塘4. jolt: n. C重击5. stun: v. 使晕倒，打晕6. prey: n.

16、猎物7. receptor: n. C接受器，感受器8. distort: v. 歪曲，误传9. obstacle: n. 障碍10. species: n.C种类11. inaudible: adj. 听不见的12. headphone: n. C听音器，耳机13. ray: n. C光线，放射线14. nerve: n. C神经15. ending: n. C末梢16. transmission: n. C传输17. impulse: n. C脉冲50Human populations near the equator have evolved dark skin over many ge

17、nerations because of exposure to the fierce rays of the Sun. A similar phenomenon has also occurred in other parts of the animal kingdom. The African grass mouse is a good example. Most mice are nocturnal, but the African grass mouse is active during daylight hours. This means that it spends its day

18、s searching for food in the semidry bush and scrub habitats of eastern and southern Africa. Its fur is striped, like a chipmunks, which helps it blend in with its environment. Because it spends a lot of time in the intense tropical sun, the grass mouse has also evolved two separate safeguards agains

19、t the Suns ultraviolet radiation. First, like the populations of humans in this region of the world, the skin of the grass mouse contains lots of melanin, or dark pigment. Second, and quite unusual, this mouse has a layer of melanin-pigmented tissue between its skull and skin. This unique cap provid

20、es an extra measure of protection for the grass mouse and three other types of African mouse-like rodents that are active during the day. The only other species scientists have identified with the same sort of skull adaptation is the white tent-making bat of the Central American tropics. Although th

21、ese bats sleep during the day, they do so curled up with their heads exposed to the sun.【生词摘录】1. nocturnal: adj. 夜行的，夜间活动的2. scrub: n. 矮树，灌丛3. fur: n. 毛皮4. stripe: v. 划条纹5. chipmunk: n. C花栗鼠6. tropical: adj. 热带的7. ultraviolet: adj. 紫外线的8. melanin: n. C黑色素9. pigment: n. C色素10. tissue: n. C【生】组织11. sk

22、ull: n. C头骨8Before starting our tour of Monticello, Id like to give you some historical facts that might help you appreciate what you see today even more. Monticello was the very much loved home of Thomas Jefferson for over fifty years. Jefferson, who was, of course, President, was also a great read

23、er and language enthusiast. He read widely on different subjects, including architecture. He wasnt formally trained in architecture, but as a result of his study and observation of other buildings, he was able to help design and build the house. He chose the site himself, naming the estate Monticell

24、o, which means little mountain in Italian. In fact, many of the ideas behind the design also came from the Italian architect Andrea Palladio, who lived in the sixteenth century and who had a great influence on the architecture of England. Jefferson, however, ignored one of Palladios principles, that

25、 is, not to build in a high place. Monticellos elevation made the transportation of what was needed at the housefor example, foodespecially difficult. But the view from the estate would not be as spectacular if Jefferson had followed Palladios advice; there really is no boundary between the house an

26、d the nature around it, and so Jefferson was able to look out on his beloved state of Virginia from his wonderful vantage point. Now well go on to Jeffersons library.【生词摘录】1. Monticello: 蒙提切娄2. appreciate: v. to understand how good or useful someone or something is 欣赏，赏识，鉴赏3. enthusiast: n. Csomeone

27、 who is very interested in a particular activity or subject 热衷于的人4. estate: n. Ca large area of land in the country, usually with one large house on it and one owner （在乡村附有宅地的）一大片私有土地，庄园5. elevation: n. singulara height above the level of the sea 海拔6. spectacular: adj. very impressive and exciting 壮

28、观的，精彩的，引人注目的7. vantage point: a good position from which you can see something （能观察某物的）有利位置15Im glad you brought up the question of our investigations into the makeup of the Earths interior. In fact, since this is the topic of your reading assignment for next time, let me spend these last few minute

29、s of class talking about it. There were several important discoveries in the early part of this century that helped geologists develop a more accurate picture of the Earths interior. The first key discovery had to do with seismic waves. Remember they are the vibrations caused by earthquakes. Well, s

30、cientists found that they traveled thousands of miles through the Earths interior. This finding enabled geologists to study the inner parts of the Earth. You see, these studies revealed that these vibrations were of two types: compression or P waves and shear or S waves. And researchers found that P

31、 waves travel through both liquids and solids, while S waves travel only through solid matter. In 1906, a British geologist discovered that P waves slowed down at a certain depth but kept traveling deeper. On the other hand, S waves either disappeared or were reflected back, so he concluded that the

32、 depth marked the boundary between a solid mantle and a liquid core. Three years later, another boundary was discovered, that between the mantle and the Earths crust. Theres still a lot to be learned about the Earth. For instance, geologists know that the core is hot. Evidence of this is the molten lava that flows out of volcanoes. But were still not sure what the source of the heat is.【生词摘录】1. makeup: n. singulara particularly co