题目

下图是反射弧结构模式图。a、d分别是放置在传出神经和骨骼肌上的电极，用于刺激神经和骨骼肌；b是放置在传出神经上的电流计，用于记录神经兴奋电位；c为神经与肌细胞接头部位，是一种突触。   （1）用a刺激神经，产生的兴奋传到骨骼肌引起的收缩  __    (属于或不属于)反射。 （2）用d刺激骨骼肌，   ___   (能或不能)在b处记录到电位。原因是   __  ___   。 （3）正常时，用a刺激神经会引起骨骼肌收缩；传出部分的某处受损时，用a刺激神American cities are similar to other cities around the world. In every country cities reflect the values of the culture. Cities contain the very best aspects of a society: opportunities for education, employment and entertainment. They also contain the very worst parts of a society: violent crime, racial(种族) conflict and poverty. American cities are changing just as American society is changing.　　 After World War II city residents became wealthier. They had more children. They needed more space. They move out of their apartments in the city to buy their own homes. They bought houses in the suburbs areas near a city where people live. These are areas without many offices or factories. During the 1950s the American “dream” was to have a house in the suburbs. Now things are changing. The children of the people who left the cities in 1950s are now adults. They unlike their parents want to live in the cities. Many young professionals, doctors, lawyers and executives(主管人员) are moving back into the city. Many are single; others are married but often without children. They prefer the city to the suburbs because their jobs are there; they are afraid of the fuel shortage; or they just enjoy the excitement and opportunities which the city offers. This population shift(转变) is bringing problems as well as benefits. Countless poor people must leave their apartments in the city because the owners want to sell the buildings or make apartments for sale instead of for rent. In the 1950s, many poor people did not have enough money to move to the suburbs; now many of these people do not have enough money to stay in the cities. Only a few years ago, people thought that the older American cities were dying. Some city residents now see a bright, new future. Others see only problems and conflicts. One thing is for sure：many dying cities are alive again. 60. What does the author think of cities all over the world? A. They are alive.　 B. They are hopeless.　 C. They are similar 　　 D. They are different. 61. Why did American city residents want to live in the suburbs after World War II? 　 A. Because older American cities were dying. 　 B. Because they were richer and needed more space. 　 C. Because cities contained the worst parts of society. 　 D. Because they could hardly afford to live in the city. 62. According to the 4th paragraph, a great many poor people in American cities ___________. 　 A. are faced with housing problems B. are faced to move to the suburbs 　 C. want to sell their buildings　　 D. need more money for daily expenses 63. We can conclude from the text that ____________. 　 A. American cities are changing for the worse 　 B. people have different views on American cities 　 C. many people are now moving from American cities 　 D. the population is decreasing in older American cities