题目

如果方程x＋y＝－1，2x－y＝4和x－my＝7有公共解，那么m的值为()A. 4 B. 3 C. 2 D. 1 答案：【答案】B【解析】将x+y=-1，2x-y=4组成方程组，求出x、y的值，再代入x-my=7，求出m的值．根据题意，解方程组，得： ，将代入x-my=7，得：1+2m=7，解得：m=3，故答案为：3． Informal conversation is an important part of any business relationship. Before you start a discussion, however, make sure you understand which topics are suitable and which are considered taboos(禁忌) in a particular culture. Latin Americans enjoy sharing information about their local history, art, and customs. They expect questions about their family and are sure to show pictures of their children. You may feel free to ask similar questions of your Latin American friends. The French think of conversation as an art form, and they enjoy the value of lively discussions as well as disagreements. For them, arguments can be interesting — and they can cover pretty much or any topic — as long as they occur in a respectful and intelligent manner. In the United States, business people like to discuss a wide range of topics, including opinions about work, family, hobbies, and politics. In Japan, China, and Korea, however, people are much more private. They do not share much about their thoughts, feelings, or emotions because they feel that doing so might take away from the harmonious business relationship they’re trying to build. Middle Easterners are also private about their personal lives and family matters. It is considered rude, for example, to ask a businessman from Saudi Arabia about his wife or children. As general rule, it’s best not to talk about politics or religion with your business friends. This can get you into trouble, even in the United States, where people hold different views. In addition, discussing one’s salary is usually considered unsuitable. Sports is typically a friendly subject in most parts of the world, although be careful not to criticize a national sport. Instead, be friendly and praise your host’s team. 1. The author considers politics and religion ________. A. cheerful topics　　　　　　 B. taboos C. rude topics 　　　　　　 D. topics that can never be talked about 2. Which is typically a friendly topic in most places according to the author? A. Sports.　 B. Children. 　 C. Personal feelings.　 D. Families. 3. Why are people from Asia more private in their conversation with others? A. They don’t want to talk with others much. B. They don’t want to have their good relationship with others harmed by informal conversation. C. They are afraid to argue with their colleagues. D. They want to keep their feelings to themselves. 4. What shouldn’t you do when talking about sports with colleagues from another country? A. Praising your own country’s sports.　 B. Criticizing your own country’s sports. C. Praising the sports of your colleagues’ country. D. Criticizing the sports of your colleagues’ country.