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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. By "his outdoor cousins" the author means______.
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Passage 38 Animals do many useful and entertaining jobs. (38) Dogs are particularly valuable in guiding the blind (a trained dog can learn never to cross a busy street when cars are coming, even if his master commands him to do so), protecting property, finding lost people, and hunting criminals. Horses are used in guarding herds, carrying men in lands where there are no roads, and helping farmers plow fields. Pigeons have long been used to carry message. Wild animals from the jungles, forests and seas are very popular performers in circuses and movies. People realize that, although animals may not have the same intelligence as human beings, they are smart enough to learn certain things. The first thing a dog is taught is to obey. It should not take too long for him to learn commands. Simple orders, such as "sit, lie down, stay there, come here" can even be taught by a child. Training a dog to be a watchdog often produces unexpected results. Some dogs quickly learn the difference between unwanted people and friends. This is because their masters welcome friends and invite them into their houses. However, some dogs will always attack the postmen who come to deliver letters. One explanation for this behavior is that, although the postman comes to the house frequently, he never enters the house. Therefore, the dog thinks the postman is someone who is not wanted, but keeps coming back anyway. Masters of dogs who attack postmen can easily show the dogs that the postman is a friend and the dog does not need to treat him as an unwanted person. A dog is quite ready to do what his master wishes. And a dog is always happy when he is praised for proper understanding. A dog feels the happiest if, after he has worked well,______.
Passage 46 Although Beethoven could sit down and make up music easily, his really great compositions did not come easily at all. They cost him a great deal of hard work. We know how often he rewrote and corrected his work because his notebooks are still kept in museums and libraries. He always found it hard to satisfy himself. When he was 28, the worst difficulty of all came to him. He began to notice a strange humming(嗡嗡声) in his ears. At first he paid little attention; but it grew worse, and at last he consulted doctors. (46) They gave him the worst news any musician could bear: he was gradually going deaf. Beethoven was in despair; he was sure that he was going to die. He went away to the country, to a place called Heiligenstadt, and from there he wrote a long farewell letter to his brothers. He longed to die, and said to death, "Come when you will, I shall meet you bravely." In fact, Beethoven did something braver than dying. He gathered his courage and went on writing music, though he could not hear what he wrote. He wrote his best music, the music we remember him for, after he became deaf. The music he wrote was very different from any that had been composed before. Which of the following statements is true
Passage 38 Animals do many useful and entertaining jobs. (38) Dogs are particularly valuable in guiding the blind (a trained dog can learn never to cross a busy street when cars are coming, even if his master commands him to do so), protecting property, finding lost people, and hunting criminals. Horses are used in guarding herds, carrying men in lands where there are no roads, and helping farmers plow fields. Pigeons have long been used to carry message. Wild animals from the jungles, forests and seas are very popular performers in circuses and movies. People realize that, although animals may not have the same intelligence as human beings, they are smart enough to learn certain things. The first thing a dog is taught is to obey. It should not take too long for him to learn commands. Simple orders, such as "sit, lie down, stay there, come here" can even be taught by a child. Training a dog to be a watchdog often produces unexpected results. Some dogs quickly learn the difference between unwanted people and friends. This is because their masters welcome friends and invite them into their houses. However, some dogs will always attack the postmen who come to deliver letters. One explanation for this behavior is that, although the postman comes to the house frequently, he never enters the house. Therefore, the dog thinks the postman is someone who is not wanted, but keeps coming back anyway. Masters of dogs who attack postmen can easily show the dogs that the postman is a friend and the dog does not need to treat him as an unwanted person. A dog is quite ready to do what his master wishes. And a dog is always happy when he is praised for proper understanding. Sometimes dogs can______.
Passage 30 Elephants are the biggest animals that live on land (some whales are bigger than elephants but whales live in the sea), when born a baby elephant weighs 91 kilograms. That is the weight of a grown man. It is about 91 centimeters high. When it reaches the age of six years, it is about 183 centimeters high. (30) When it reaches the age of twelve years, it does not grow any more. It may then be 320 centimeters high. African elephants are bigger than Indian elephants. African elephants have much bigger ears. Elephants have very long noses which we call "trunks". No other animals have trunks as long as elephants. An elephant can use its trunk to smell things and it can also pick up things with the tip of its trunk. The tip of its trunk can be used like a hand. An elephant uses its trunk to feed itself. It likes to eat leaves, young juicy branches of a tree and fruit. It picks these with its trunk and puts the food into its mouth. When it wants a drink, it puts the tip of its trunk into water. It fills its trunk with water and then blows the water into the mouth. The elephant washes itself in the same way. It fills its trunk with water and then blows the water over itself. Two of the elephant’s teeth are very long and strong. They are called "tusks". They use their tusks to dig up small trees and to dig in the ground for water. Elephants also use their tusks to lift heavy logs of wood. In some countries men catch wild elephants and teach them to work. After a while they are no longer wild. They become tame. They become very obedient. They do what their masters tell them to do. All day long they work patiently in the hot sun. They pull trees along and lift heavy logs. No animal is stronger than an elephant. Elephants have very strong legs. Their legs are like trees. They usually walk slowly because they are so big, but they walk very quietly. People teach elephants to work because______.
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