题目内容
（请给出正确答案）
Pigeons have a natural instinct for ______.
A．going back home
B．growing fast
C．flying at a high speed
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更多“Pigeons have a natural instinct for ______.A．going back homeB．growing fastC．flying at a hi”相关的问题
A.A know what they want to achiev
B.B are more competitive by natur
C.C have more individual talen
D.D can be driven by national prid
Pigeons have been known to fly as fast as ______.
A．75 mph
B．50 mph
C．110 mph
D．62 mph
A．Y
B．N
C．NG
Science seems to be getting closer to answering a very old mystery (奥秘). Homing pigeons (信鸽) can be taken hundreds of miles from their homes. When they are let to go to fly again, they find their way home. Because of this special ability to find home, pigeons have been used as messengers for hundreds of years.
Today people even breed homing pigeons for racing as a sport. The birds are shipped to some chosen place a few hundred miles away. Then all of them are let to go together. The winner is the bird that gets home first. A good racer can make it home from 500 miles away in a single day.
The mystery of the homing pigeon is how it tells direction and how it finds home.
The first part seems to be pretty well answered, and we know of two ways that pigeons tell directions. First, they use the sun. Experiments show that homing pigeons can tell directions by the sun. What happens when the sky is darkly overcast by clouds and no one can see where the sun is？ Then the pigeons still find their way home.
Naturally, people have wondered whether pigeons might have a built-in compass—something that would tell them about the direction of the earth’s magnetic (磁的) field. Many different kinds of experiments were done. Here’s what the scientists decided after they had made experiments many times. When pigeons can see the sun, they use it as their main means(手段)of direction-finding. When they cannot see the sun, they use some special way to sense direction from the earth’s magnetic field.
But how do pigeons know which direction is toward home？ What do they use that we would call a map？ These are other questions to be answered.
Pigeons have been used as messengers because ______.
A．they have a built-in compass
B．they can cover 500 miles in a single day
C．they have special ability to tell directions
D．they can find their way home
Suppose your neighbor Uncle Li feeds many pigeons in the corridor, which interferes with your daily life quite a lot. You have communicated with him several times, but he refused to move away the pigeons. Write a letter of complaint to the Neighborhood Committee to state:
(1)a description of the situation,
(2) your complaint about the situation, and
(3) your request.
You should write approximately 100 words. Do not sign your own name at the end of the letter. Use "Wang Lin" instead. You do not need to write the address.
根据以下内容回答题：
Homing pigeons are placed in a training program from about the time they are twenty。Eight days of age．They are taught to enter the lon through a trap and to exercise above and around the loft．and graduaUy they are taken away for short distances in wicker baskets and released．They are then expected to find their way home in the shortest possible time． In their training flights or in actual races，the birds are taken to prearranged distant point sand released to find their way back to their own logs．Once the birds are liberated，their owners，who are standing by at the home lofts，anxiously watch the sky for the return of their entries．Since time is of the essence，the speed with which the birds can be induced to enter the loft trap may make the difference between gaining a win or a second place． The head of a homing pigeon is comparatively small，but its brain is one quarter large than that of the ordinary pigeon．The homing pigeon is very intelligent and will persevere to the point of stubbornness；some have been known to fly a hundred miles off course to avoid a storm． Some homing pigeon experts claim that this bird is gifted with a form. of built-in radar that helps it find its own loft ager hours of flight，for hidden under the head feathers are two very sensitive ears，while the sharp，prominent eyes can see great distances in daytime． Why do homing pigeons fly homeg They are not unique in this inherent skill；it is found in most migratory birds，in bees，ants，toads，and even turtles，which have been known to travel hundreds of miles to return to their homes．But in the animal world，the homing pigeon can be trusted with its freedom and trained to carry out the missions that people demand．
What is the purpose of the passage？
A.To convince the reader to buy a homing pigeon．
B.To inform. the reader about homing pigeons and their training
C.To protect homing pigeons against the threat of extinction（绝迹）．
D.To encourage the owners of homing pigeons to set the birds free．
Part A
Suppose your neighbor Uncle Li feeds many pigeons in his corridor, which interferes with your daily life quite a lot. You have communicated with Uncle Li, but he refused to move away the pigeons. Write a letter of complaint to the neighborhood committee. Your letter should include:
1. a description of the situation
2. complaint about the situation
3. your request
You should write approximately 100 words. Do not sign your own name at the end of the letter. Use Wang Lin instead. You don’t need to write the address.
How Birds Find Way Home？
The ability of birds to return to a familiar place from any distance is a remarkable feat of nature. For centuries people have taken advantage of this ability in homing pigeons by using them to take messages from distant points back to familiar sites. Homing pigeons are domesticated non-migratory birds with an instinct to return to their lofts (nesting sites) that is improved with training and by selective breeding. Training is started at short distances from the nesting site; over time, this distance is gradually increased to hundreds of miles from its loft at a completely unfamiliar location and it can fly in the direction of home within a minute or two of its release. How does this extraordinary behavior. work？
Understanding homing behavior. is one of the greatest challenges to ornithologists (鸟类学家). Fortunately, because they are able to carefully control the conditions under which the pigeons are released, researchers have been able to learn a great deal about how the birds navigate their way home.
Although homing ability has been fostered in pigeons by careful breeding and selecting of stock, it appears that training is not always necessary: Many species of wild birds perform. similarly remarkable feats. One such bird is the migratory Manx Shearwater (剪嘴鸥). Built like tiny albatrosses, these seabirds spend most of their lives skimming over the ocean surface far from the sight of land. They come ashore only to nest in burrows, which they dig in the ground on offshore islands in order to be safe from predators. The ease of locating and observing their nests make shearwaters ideal subjects for homing experiments.
Great Bird Navigators
Many migratory birds are remarkably faithful to previous nesting and overwintering places. Though a bird might be able to come close to these sites merely by flying in a general direction during the course of migration, at some point more sophisticated navigating techniques must take over to guide the bird to its precise destination.
Many animals are able to find their way home. One way of doing this is to directly sense the goal—to see, hear, or smell it. Another way is to memorize the details of the outward journey and then reverse the route based on an integration of that information. Birds, however, apparently rely on a completely different process to find their way. To explain bird navigation, we have what is known as the "map-and-compass" theory.
The compass component of this theory gives direction--north, south, east, west; the map component tells the bird where it is, or gives locality. Scientists have learned a great deal more about the compass component than they have about mapping. They know that birds have several means of determining compass directions, but unfortunately, they still have no satisfactory explanation for how birds use biological "maps" to guide them to a precise location from an unfamiliar starting point.
Bird Sun Navigators
Some observations indicate that birds might use the sun as, a visual cue to determine compass directions. Starlings (八哥), for example, seem able to negotiate the proper direction only if they have a view of the clear sky and sun; cloud cover seems to induce confusion. In an experiment in which the sun's apparent position was changed with mirrors attached to an orientation cage containing starlings, observers noted that the direction of the starlings' hopping, which earlier had been correlated to the direction that chose to migrate, was shifted accordingly.
Even birds that migrate exclusively at night pay considerable attention to the sun. At first this may seem odd because, after all, the sun is not visible to the nocturnal (夜间活动的) birds when they are flying. On the other hand, it is a predominant feature in the sky at a time of day (dusk)when birds may well be making decisions about w
A．Y
B．N
C．NG
听力原文： I have an announcement to make before we start class. I'm looking for a student to hire as a part-time assistant. I'm interested in someone who has at least two semesters' experience in behavioral biology. I'm studying pigeons and their methods of navigation. So I need someone who is comfortable working with birds. Even though most d the work involves research, I also expect some help in cleaning cages and feeding the binds. I'll need someone for about two hours daily, including Saturday. If you are interested, please some to see me fight after today's class.
(33)
A．A student.
B．A librarian.
C．A teacher.
D．A part-time assistant.
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