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问题 选择题

如图所示，用钓鱼杆钓鱼的时候，鱼钩已经钩住了鱼。鱼还在水中时，感觉鱼很轻，刚把鱼从水中拉离水面就感觉鱼变“重”了。下列几种解释，错误的是(    )

A．鱼离开水后，失去了水的浮力，使人感觉鱼变重了

B．鱼离开水后，鱼的重力增大，使人感觉鱼变重了

C．鱼离开水后，钓鱼线对钓鱼杆的拉力会增大

D．钓鱼杆是一种费力杠杆

答案

答案：B

重力是由于地球的吸引而使物体受到的力，鱼离开水前后受地球的吸引不变，所以重力不变。选C。

单项选择题

通过______综合管理，实现了运输企业内部一体化和外部供应链的统一管理，有效地帮助运输企业提高服务质量，提高运输企业的整体效益。

A．“点对点”的直线式
B．“点对线”的立体式
C．“面对面”的平面式
D．“点、线、面”的立体式
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单项选择题

According to the United States government, people are classified as homeless if they have no place to stay and no expectation of finding a place for the next thirty days, Although technically accurate, that is an impersonal assessment of an enormous and very human problem,
The homeless population represents all of us Americans, It includes men and women, the elderly, children, and infants. Its members are from all ethnic (种族的) groups. What they have in common is poverty.
Currently in the U.S., thirty-nine million people live in poverty. When money is really tight, paying the rent or buying food often becomes a choice. Government assistance in the form of food stamps does help but, as one homeless man explains, you can’t pay the rent with food stamps.
With no money for rent, the streets and homeless shelters become the alternative.

The breakup of families is likely to lead to homelessness because a parent with kids may ______.
A. lose his or her job in today’s economy B. be unable to look after the kids
C. not have enough incomeD. find residence at a homeless shelter

Although men constitute the largest group within the homeless population, homeless women with children are rapidly joining them. In fact, one quarter of the homeless people in the U.S. are teenagers and young children.
People may become homeless for numerous reasons. However there are certain factors that many of these individuals have in common. They include a lack of adequate education and job skills. A majority of the teenagers and adults have not completed high school.
The abuse of alcohol and drugs is also a common factor. One third of the adult homeless population abuses alcohol, while one quarter of the same group uses drugs.
Some members of this population suffer mental health problems. Within the past several years many institutions for the menially ill have been closed and their patients sent "home". Unfortunately, a number of those people have no home to go to and they are unable to adequately look after themselves.
Job loss in today’s economy has also become a real factor in the loss of people’s homes. The breakup of families through abandonment and divorce are also contributing factors, particularly when there are children involved. The parent who is left to care for the kids with inadequate income may be forced to depend on the homeless shelters to put a roof over their heads.
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