题目

如图所示，用50Hz的电磁打点计时器打出的纸带示意图，其中AB=42mm，AC=88mm，AD=138mm，vB=         m/s，vC=       m/s． 答案：2.2；2.4． Most people agree that the direct, assertive(过分自信的) American personality is a virtue, but it sometimes surprises foreigners．In many cultures, respect for older people or those in positions of authority keeps others from expressing their true feelings．But in the U．S, children often argue with their parents, students may disagree with their teachers, and citizens may express opposition to the actions of the government．If the soup has a fly in it or the  meat is too tough to chew, the diner can complain to the waiter, if the boss makes a mistake, an employee will politely point it out． Some straight talk about the American character must include the admission that Americans have their faults．The extremely competitive nature of Americans is probably their worst fault．Of course, competition isn’t always bad．As a matter of fact, it promotes excellence by encouraging individuals and businesses to try to do their best．But the desire to get ahead of others sometimes causes people to do things that are unkind and even dishonest．Also, Americans admire what is practical, fast, efficient, and fresh．Sometimes they fail to understand and appreciate practices that have greater respect for more traditional, leisurely ways of doing things．On the other hand, people from other cultures may dislike the practical, challenging American lifestyle． Despite culture differences, most foreigners give Americans credit for their virtues．Americans are generally viewed as friendly, adaptable, energetic, and kindhearted．Most newcomers to the U．S．like Americans, and the feeling is usually mutual．Perhaps the greatest American virtue is a deep interest in new ideas and new people．In a nation of immigrants, the foreigner does not remain an outsider for long． 1In order to show the respect for older people,     ． A．people from some other cultures will always express their true feeling B．people from some other cultures may sometimes hide their true feeling C．Americans always show their true feelings D．Americans usually argue with them 2Why is the extremely competitive nature considered as one of American faults? A．Because people from other cultures fear competition． B．Because only American people own it． C．Because it will make people forget leisure． D．Because it may sometimes urge people to do something bad． 3It can be inferred from the passage that ．       ． A．American people are more critical of everything than people from other cultures B．the author believes that American character has more faults than virtues C．the author admires American virtues as they are viewed as competitive and anti traditional D．it is difficult for newcomers to get on with Americans 4The passage mainly talks about．      ． A．American virtues  B．American characters  C．American faults     D．American lifestyles