题目

将离心率为的双曲线的实半轴长a和虚半轴长b 同时增加m 个单位长度，得到离心率为的双曲线，则（   ） A．对任意的a，b，    B．当 时，；当时， C．对任意的a，b，    D．当 时，；当时， 答案：BDo you have any foreign friends? Do you know their characteristics(特征)? The Germans are very quiet and they always keep calm. They don’t like to speak more words. They look very serious. They like different kinds of amusements. The Germans are very hard—working. They like tidiness, especially the women, who always keep their home clean. In some ways, the Englishmen look the same as the Germans. They are very quiet and never talk too much with the strangers. They are really polite, so we often hear they say “Thank you.” Or “Sorry.” The gentlemen are also the Englishmen. The French’s holidays are very long. They like traveling and usually spend their long time staying in other countries. The Frenchmen are more outgoing than the Germans. It is very easy to make friends with them. Compared to the Frenchmen, the Americans are more outgoing. And they are even opener than all of the Europeans. They don’t like to depend on others. So it is very common that the students do part-time jobs in their free time. And in Americans’ eyes, success is an important part in their life. 1.According to the passage, ______are very quiet. A．only the Germans B．only the Englishmen C．only the Frenchmen D．both the Germans and the Englishmen 2.In the writer’s eyes, the gentlemen are______. A．the Germans B．the Frenchmen C．the Englishmen D．the Americans 3.What can we learn about the Frenchmen from the passage? A．They are more outgoing than the Americans. B．It is very easy to make friends with them. C．They like traveling in their own country. D．They look serious and are always hard-working. 4.Which is the best title of the passage? A．Foreigners’ hobbies. B．Who are more outgoing? C．Characteristics of the foreigners. D．Success is an important part in Americans’ life.