When animals make long journeys across places where there is no food or shelter, such as deserts or oceans, it is very important that they should be able to find their way accurately.
Birds find their way by the stars at night and by the sun during the day. People thought that this was impossible. Then some scientists made an experiment. They put some migrating birds(候鸟)in cages inside a planetarium(天象图). When the operator turned the artificial sky(人造天空)round, the birds began to fly to the sides of the cage. Every time he moved it, the birds moved to a new position. Scientists discovered that they always flew toward the direction in which they would have flown if the sky had been real. This proved that they could see the stars and respond to them.
Many animals, especially birds, have a very precise sense of time, which is called their “internal clock”. In cloudy weather, birds delay setting off on long journeys, but if the cloud lasts for a long time,
A. Birds find their way by the stars at night and by the sun during the day.
B. Birds can tell the differences between real sky and artificial sky.
C. Birds can see the stars and would move when the stars change position.
D. Birds always fly to the sides of the cage.
When animals make long journeys across places where there is no food or shelter, such as deserts or oceans, it is very important that they should be able to find their way accurately.
Birds find their way by the stars at night and by the sun during the day. People thought that this was impossible. Then some scientists made an experiment. They put some migrating birds(候鸟)in cages inside a planetarium(天象图). When the operator turned the artificial sky(人造天空)round, the birds began to fly to the sides of the cage. Every time he moved it, the birds moved to a new position. Scientists discovered that they always flew toward the direction in which they would have flown if the sky had been real. This proved that they could see the stars and respond to them.
Many animals, especially birds, have a very precise sense of time, which is called their “internal clock”. In cloudy weather, birds delay setting off on long journeys, but if the cloud lasts for a long time,
A. Birds find their way by the stars at night and by the sun during the day.
B. Birds can tell the differences between real sky and artificial sky.
C. Birds can see the stars and would move when the stars change position.
D. Birds always fly to the sides of the cage.
Roman soldiers in some places built long rows of signal towers. When they had a message to send, the soldiers shouted it from tower to tower. If there were enough towers and enough soldiers with loud voices, important news could be sent quickly over distance.
In Africa, people learned to send messages by beating on a series of large drums (鼓). Each drum was kept within hearing distance of the next one. The drum beats were sent out in a special way that all the drummers understood. Though the messages were simple, they could be sent at great speed for hundreds of miles.
In the eighteenth century, a French engineer found a new way to send short messages. In this way, a person held a flag in each hand and the arms were moved to various positions representing different letters of the alphabet (字母表). It was like spelling out words with flags and arms.
Over a long period of time, people sent messages by all these different ways. However, not until the telephone
A. fine weather
B. high tower
C. the spelling system
D. arm movements
When you make your travel arrangements to Oxford, Ohio, you should make plans to arrive here at least a week before classes begin so you can get to know the university and the area. The university holds a short orientation program for all new foreign students prior to registration for classes, and you will be expected to attend this program.
A valuable service to foreign students traveling to the U. S. is provided by the International Students Service (ISS) in New York. If you Send your travel plans to the ISS, someone will meet you at your port of entry to the U. S. , help you find a temporary place to stay, help you arrange your travel within the U. S. , and provide other assistance. There is no charge for these services. For more information, contact..
International Students Service
356 West 34 th Street , Third Floor
New York, New York 10017 USA
When you arrive in Oxford, you should first visit the Office of International Studen
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