题目

下列运算正确的是（   ） A．x10÷x5=x2；  B．x-4·x=x-3；  C．x3·x2=x6；  D．（2x-2）-3=-8x6 答案：B（点拨：x-4·x=x-4+1=x-3．x的指数是1，易错看成0；A错在将指数相除了；C错在将指数相乘了；D中，）阅读理解。     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 animpersonal 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 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, asone 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.      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 US are teenagers and young children.      People may become homeless for numerous reasons. However, there are certain factors that many of theseindividuals have in common. They include a lack of adequate education and job skills. A majority of the teenagersand adults have not completed high school. The abuse of alcohol and drugs is also a common factor. One thirdof 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 manyinstitutions for the mentally ill have been closed and their patients sent "home". Unfortunately, a number of thosepeople 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 offamilies through abandonment and divorce are also contributing factors, particularly when there are childreninvolved. The parent who is left to care for the kids with inadequate income may be forced to depend on thehomeless shelters to put a roof over their heads. 1. The writer thinks that the US government's definition for the homeless reveals _____. A. an insincere attitude toward the homeless B. an unbearable attitude toward the homeless C. an uncivilized attitude toward the homeless D. an unsympathetic attitude toward the homeless 2. The US government helps the homeless by _____. A. giving them homeless allowance B. giving them food stamps C. finding jobs for them D. finding residence for them 3. People become homeless for all the following reasons EXCEPT _____. A. the lack of adequate education B. the abuse of alcohol and drugs C. the closure of institutions for the mentally ill D. the poor performance of economy 4. 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 income D. find residence at a homeless shelter