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. a clock that is built inside the bird
B. a clock that tells correct time
C. an exact sense of direction
D. an accurate sense of time
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
W: When a couple runs into marriage problems, where should they turn
M: The primary source of help should be the couple themselves. The last book I wrote, Four Weekends to an Ideal Marriage, describes how people can strengthen communication by setting aside a special time or place to meet and discuss their relationship. If they cannot communicate verbally, they might at least write down a list of things that they feel have gone wrong in the marriage. The idea is to discuss these matters constructively, not to be vicious in the criticism. Some church groups have been very successful with marriage encounter weekends that help couples with this process.
W: What if a couple can’t work things out for themselves
M: If people feel so hitter that they cannot even talk with each other, they should consider very seriously a qualified psychologist. And I stress qualified, because there are a lot of unqualified out there who can make things worse. The best appro
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