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70天攻克考研英语阅读 DAY13

2006-7-28 01:03  

  Increasing reading speed

  Directions: Do the phrase recognition drill below. Quickly underline or mark the phrase every time it appears in the columns. Try to finish in 10 seconds or less by reading down the column, not left to right.

  Starting Time:

  Key Phrase: bird migrationbird mysteriesstamp collection

  bird migration        stamp collector

  bird migration        bird migration

  good migrator        bird migration

  animal migration      unsolved mysteries

  bird migration        nature mysteries

  bird migration        natural science

  natural history        birth control

  bird migration        chain reaction

  birthdeath radio      bird migration

  black cutworm        fusion reaction

  radar navigation        bus station

  bird migrations        swallow migration

  swan migration        bird migration

  Finishing Time:  Total Reading Time:

  Check each line very carefully. Key phrase appears 10 times.

  Mysteries of MigrationWinter weather comes with its extreme coldness and low supply of food. Since most animals cant survive in it, they either sleep through it or migrate.

  The urge to migrate is very strong in some birds. Each year the tern can produce offspring only during a twomonth time period. During those two months the tern lives in the region near the North Pole. In the ten months between this time and the next, he flies all the way from the North Pole to the South Pole, and then back north again. This is a distance of about 22,000 miles. To accomplish this, the tern must fly about 75 miles every day for ten months.

  What must it be like to be a tern? There you are up on the Arctic Ocean covered with silverwhite, gray and black feathers; with a straight pink beak and delicate pink feet, hard some, wellfed, and perfectly satisfied with the cold of the short North Pole summer. The block of ice you are resting on lifts and falls slowly on the waves of the Arctic Ocean.

  You are comfortable there on the ice block. But the urge to migrate hits you with full force. Every part of your tern body is urging you to fly - to migrate south. And it is a good thing it is, because the sky is beginning to show that the cold, dark Arctic winter is coming soon.

  So off you go along with all the other terns. You fly down a path that Arctic terns have always taken, down the west coast of North America and then down along South America. The other terns are crossing the Atlantic and flying down the west coasts of Europe and Africa.

  How do birds know when to migrate? How do they find their way on such long trips? And why do they come back from those warm comfortable places?

  Some birds find their way by the position of the sun in the sky. But most birds migrate at night. Apparently they navigate by the stars just as pilots of ships do.

  What makes a bird migrate? Studies in New York State show that it is the birds biological time clock that does it. A bird specialist kept some birds in a planetarium. He was surprised to find that they didnt pay any attention to the stars in the ceiling when migration time came. But then he gradually gave them periods of false daylight, making the days shorter and shorter, as they are in the fall. Within a few weeks the birds tried their best to fly south. He also found that the birds navigate by the North Star once they get the urge to migrate. In fact, when the North Star was removed from the false sky, the birds became completely confused and flew in all different directions.

  If things are so good in the warm climates that birds return there every winter, why do they come back north every spring? The warm region is crowded with birds, and the short winter stay of the migrants puts space and food on short supply. The area also has many turtles, snakes, and other animals that steal from bird nests, so birds return north to lay their eggs.

  Bird migration is the most familiar kind of migration. But other animals migrate too. Every fall monarch butterflies all over Canada and the United States take an extremely long migration trip. They start out singly, then join others in crowds, moving in great numbers through the skies. Sometimes the butterflies fly in a single line like pelicans in a group flying, and other times they crowd together in thick black clouds, then stop in trees, making the covered branches move as if they were living.

  When you hold a butterfly in your hand and see the thin wings you wonder how the butterflies can make these long trips. But they fly thousands of miles, often at ten to forty miles an hour. No one knows how they find their way to the same places in California, Florida, and Mexico - but they do. And as did their parents and grandparents, they not only go to the same towns for the winter, but sometimes even land in the same trees. In the spring the butterflies leave the trees and return north again. There they lay their eggs on young plants that are just coming up above the ground. After they lay their eggs, they die.

  ——from English of Science and Technology, No. 4, Nov. 1981

  Time:  754 words = wpm

  Minutes

  EXERCISESⅠ。 READING COMPREHENSION

  Select the answer which is most accurate according to the information given in the passage.

  1. Each year the terns spends two months time in or around the Arctic Circle in order to .

  A. accumulate enough fat for the next journey

  B. set off the next spring

  C. mate, lay their eggs, and raise their young

  D. wait till their young grow fullfledged

  2. The distance a tern covers from the North Pole to the South Pole is approximately miles.

  A. 5,500B. 11,000C. 22,000D. 44,000

  3. According to the passage, it is  that helps a bird decide when to migrate south.

  A. the change in the duration of daytimeB. the change in the location of the North

  C. the removal of the North Star from the simulated sky in the planetarium

  D. the approaching cold weather

  4. Which of the following is true, according to the bird specialist?

  A. The birds he experimented on judged their flying route by the North Star.

  B. As the surrounding temperature in the planetarium was kept constant, the birds had no behavioral changes when the migration time arrived.

  C. When the birds saw the North Star fixed in the false sky they started flying south no matter what season it was.

  D. As the days were reduced to become shorter and shorter and the surrounding temperature lower and lower, the birds thought that fall was coming and began flying south.

  5. Migrating birds fly up north again in the spring because of .

  A. the overly dense population of different kinds of birds in the warm region

  B. the shortage in food supply

  C. the fear of their natural enemiesD. all the above

  6. When the monarch butterflies begin their long journey, .

  A. they set out together, forming a single moving line

  B. they set off together in thick, black clouds

  C. they start out separately, then get closer to each other in crowds

  D. they set out one at a time, stopping in trees from time to time to rest their wings

  7. According to the passage, .

  A. scientists have already uncovered the mystery of how monarch butterflies find their way to the same places in America

  B. no one really understands how monarch butterflies find their way to the same places as did their parents and grandparents

  C. the butterflies fly down south again after laying their eggs

  D. female butterflies lay their eggs on young plants in the south

  Ⅱ。 CONTEXTUAL REFERENCE

  Read the following two short passages and figure out the meaning of each word in italics using the context given and wordbuilding skills.

  (A)

  Anyone can watch an ant making its way back to the nest in a garden or woodland, but a more convenient animal for experiments is the honeybee. Bees can be trained to come to a source of food which can then be moved about. Their hive can also be moved and in this way the bees orientation is affected at both ends of the journey. From the simple observations showing that insects steer a course by using a form of sun compass, details of the way this compass works have been explained - although the explanation cannot be completed until the mechanism (机理;机制) of the insects compound eye is fully understood.

  ——from Further Scientific English Practice, p. 137

  (B)

  It has been suggested that birds can sense the magnetic lines of force stretching from the north to south magnetic poles of the earth, and so direct themselves. But all experiments until this time made to see whether magnetism has any effect whatsoever on animals have given negative results. Still, where there is such a biological mystery as migration, even improbable experiments are worth trying. Research was being done in Poland, before the invasion of that country, on the possible influence of magnetism on pathfinding. Magnets were attached to the birds heads to see whether their directionsense was confused thereby. These unfinished experiments, of course,  had to be stopped.

  ——from Scientific English Practice, p. 21

  Ⅲ。 CLOZE

  Complete the following passage by filling in the blanks with appropriate words.

  Animals Sense of Magnetism

  One of natures greatest mysteries is how birds and other animals find their way when they travel hundreds or thousands of kilometers to their summer or winter homes. Some scientists say these animals somehow use the earths magnetic forces to guide themselves.

  Scientists in California recently      1     magnetic material     2     the heads of dolphins. The scientists believe the material     3     the sea creatures to know     4     they are.

  The California scientists say the     5     in the dolphins brains are    6     a  form of iron and 7. Magnetite acts like a     8     : an instrument that is sensitive     9     the pull of the earths 10     poles. Magnetite has been     11 other creatures:      12     birds, honeybees and     13      bacteria, but it is the first time     14     material has been found in a warmblooded     15    like the dolphin. The scientists in California made their     16     while examining the     17     of four Pacific Ocean dolphins that died     18     natural causes. In three of the dolphins, the scientists found tissue   19   the brain that appeared to be     20     to magnetism. In the fourth dolphin, the researchers discovered a tiny piece of magnetite. The scientists say the magnetite piece was connected to what appeared to be nerve tissue.

  The California scientists are not exactly sure how the magnetic material affects the nerve tissue and influences the dolphin. But they believe the piece of magnetite may move under the force of the earths magnetic field. This movement, they say, is a signal to the creature, telling the dolphin in which direction to swim.

  ——from The Voice of America, Jan. 15, 1982

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