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Passage 37 Why don’t birds get lost on their long flights from one place to another Scientists have been puzzled over this question for many years. Now they’re beginning to fill in the blanks. Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly by night (37) Tests with artificial stars have proved that certain night-flying birds are able to follow the stars in their long-distance flights. A dove had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight. The stars are apparently their principal means of navigation. When the stars are hidden by clouds, they seemingly find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way. The reason why birds don’t get lost on long flights______.
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Passage 43 Sometimes it is impossible to send all the mail that arrives at the post office. Perhaps there is an inadequate or illegible address and there is no return address. The post office cannot just throw the mail away, so it becomes "dead mail". Dead mail is then sent to one of the U.S. Postal Service’s dead mail offices in Atlanta, New York, Philadelphia, St. Paul, and San Francisco. Seventy-five million pieces of mail can end up in these offices in one year. The staff ’of the dead mail offices has different ways to deal with all of these pieces of dead mail. First of all, they look for clues that can help them deliver the mail; they open packages in the hope that something inside will show where the package came from or is going to. (43) Dead mail will also be listed on a computer so that people can call in and cheek to see if a missing item is there. However, all of the mail cannot simply be stored forever: there is just too much of it. When a lot of dead mail has piled up, the dead mail offices hold public auctions. Every three months, the public is invited to the offices and containing items found in dead mail packages are sold to the highest bidder (出价人). Which is the best title for the passage
Passage 29 The first English window was just a slit in the wall. (29) It was cut long, so that it would let in as much light as possible, and narrow, to keep out the bad weather. However, the slit let in more wind than light. This is why it was called "the wind’s eye". The word window itself comes from two Old Norse words for wind and eye. Before windows were used, the ancient halls and castles of northern Europe and Britain were dark and smoky. Their great rooms were high, with only a hole in the roof to let out the smoke from torches and cooking fires. As time went on, people wanted more light and air in their homes. They made the wind’s eyes wider so as to admit air and light. They stretched canvas across them to keep out the weather. The underlined word "canvas" probably means______.
Passage 23 In order to learn a foreign language well, it is necessary to overcome the fear of making mistakes. (23) If the primary goal of language use is communication, then mistakes are secondary considerations that may be dealt with gradually as awareness of those mistakes increases. On the other hand, students should not ignore their mistakes. The language learner may observe how native speakers express themselves, and how native expressions differ from the way the learner might say them. For example, a Spanish speaker who has been saying "I do it" to express willingness to do something in the immediate future, could, by communicating with native speakers of English, observe that native speakers actually say "I’ll do it". This difference can serve as a basis for the student to change his way of using the present tense in English. But a student who is unwilling to communicate in the first place would lose this opportunity to learn by trial and error. The author’s major conclusion about the function of mistakes in foreign language learning is that______.
Passage 42 Some countries have large numbers of earthquakes. Japan is one of them. Others do not have many; for example, there are few earthquakes in Britain. There is often a great noise during an earthquake. The earth shakes. Houses fall down. Railway lines are broken. Sometimes many people are killed in an earthquake. Earthquakes often happen near volcanoes, but this is not always true. The centers of some are under the sea. The bottom of the sea suddenly moves. The powerful forces inside the earth break the rocks. The coast is shaken and great waves appear. These waves travel long distances and rush over the land when they reach it. (42) They are strong enough to break down houses and other buildings; sometimes they break more buildings than the earthquake itself. What kind of buildings stands up best in an earthquake A building with concrete walls is perhaps the best. A steel frame will make it even stronger. The frame holds the different parts together, and the walls do not easily fall. There is less chance of fire because concrete and steel do not burn. This kind of building is the safest. The waves caused by an earthquake______.
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