题目内容

A A volcanic eruption in Iceland has sent ash across northern Europe.Airlines have stopped or changed the flights across the Atlantic Ocean,leaving hundreds of passengers stuck in airports. Grimsvotn is one of the largest active volcanoes in Europe.What makes Grimsvotn different is that it lies under a huge glacier(冰川) of ice up to 12 meters thick.The hot volcano heats up the ice above it,which then forms a layer(层) of water between the glacier and the volcano.This layer of water puts pressure on the volcano,keeping it stable.As the water flows out from under the glacier,the pressure lifts.The lava(岩浆) from the volcano then comes up to the surface.This is exactly what has happened today. Now,airlines have to make changes to their flights so as not to fly through the clouds of volcanic ash.According to KLM,one of Europes biggest airlines,airplanes cannot go under the cloud or over it.Going through the cloud can result in ash getting stuck in the airplanes engines,causing damage to the plane. The eruption has also caused problems for animals in Iceland.The volcano left ash and sharp,glasslike rocks all over the countryside.Farmers are keeping their animals inside to stop them from eating ashcovered grass or the sharp objects. What keeps Grimsvotn still

A. The slow flow of water.
B. The low water temperature.
C. The thick glacier.
D. The water pressure.

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模拟彩色电视制式中,()制式的场扫描频率为50场/秒。NTSC制式的电视信号帧速率为(),通常胶片电影的快门速率为()。 通常胶片电影的快门速率为()。

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Many theories concerning the causes of juvenile delinquency crimes committed by young people focus either on the individual or on society as the major contributing influence. Theories 16 on the individual suggest that children engage in criminal behavior 17 they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through 18 with others. Theories focusing on the role of society suggest that children commit crimes in 19 to their failure to rise above their socioeconomic status 20 as a rejection of middleclass values. Most theories of juvenile delinquency have focused on children from disadvantaged families, 21 the fact that children from wealthy homes also commit crimes. The latter may commit crimes 22 lack of adequate parental control. All theories, however, are tentative and are 23 to criticism. Changes in the social structure may indirectly 24 juvenile crime rates. For example, changes in the economy that 25 to fewer job opportunities for youth and rising unemployment 26 make gainful employment increasingly difficult to obtain. The resulting discontent may in 27 lead more youths into criminal behavior. Families have also 28 changes these years. More families consist of oneparent households or two working parents; 29, children are likely to have less supervision at home, 30 was common in the traditional family 31. This lack of parental supervision is thought to be an influence on juvenile crime rates. Other 32 causes of offensive acts include frustration or failure in school, the increased 33 of drugs and alcohol, and the growing 34 of child abuse and child neglect. All these conditions tend to increase the probability of a child committing a criminal act, 35 a direct causal relationship has not yet been established.

A. assessable
B. identifiable
C. negligible
D. incredible

B In choosing a friend, one should be very careful. A good friend can help you study. You can have fun together and make each other happy. Sometimes you will meet fair weather friends. They will be with you as long as you have money or luck, but when you are down, they will run away. How do I know when I have found a good friend I look for certain qualities of character, especially understanding, honesty and reliability. Above all else, I look for understanding in a friend. A good friend tries to understand how another person is feeling. He is not quick to judge. Instead, he tries to learn from others. He puts himself in the other persons place, and he tries to think of ways to be helpful. He is also a good listener. At the same time, however, a good friend is honest. He does not look for faults in others. He notices their good points. In short, a friend will try to understand me and accept me. Another quality of a friend is reliability. I can always depend on a good friend. If he tells me he will meet me somewhere at a certain time, I can be sure that he will be there. If I need a favor, he will do his best to help me. If I am in trouble, he will not run away from me. There is a fourth quality that makes a friend special. A special friend is someone with whom we can have fun. We should enjoy our lives, and we would enjoy our friendship. That is why I especially like friends who are fun to be with. A good friend likes the same things I like. We share experience and learn from each other. A good friend has a good sense of humor, too. He likes to laugh with me. That is how we share in the joy of being friends. And I know that he is looking for the same quality in me. When I meet someone who is reliable, honest, and understanding, I know Ive found a friend! This passage mainly discuss .

A. the qualities of a friend
B. where to choose friends
C. how to get along with friends
D. the importance of having a friend

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