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问题 单项选择题

“一场春雨一场暖”描述的天气系统是（）

A、气旋

B、反气旋

C、冷锋

D、暖锋

答案

参考答案：D

解析：

一场春雨一场暖”，此天气系统过后，气温回升，天气转晴，为暖锋。

点评：本题难度较小，解答本题的关键是通过锋面过境前后气温的变化判断为暖锋。

单项选择题

一般情况下，使用( )建立表结构，要详细说明每个字段的字段名和所使用的数据类型。

A．“数据表”视图

B．“设计”视图

C．“表向导”视图

D．“数据库”视图
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问答题

Man first appeared on the earth about 2 million years ago. Then he was little more than an animal; but early man had a big advantage over the animals. He had in his brain special groups of nerve cells, not present in animals that enabled him to invent a language and use it to communicate with his fellow men. 46) This ability to speak was of great value because it allowed men to share ideas, and to plan together, so that tasks impossible for a single person could be successfully undertaken by intelligent team-work. Speech also enabled ideas to be passed on from generation to generation so that the stock of human knowledge slowly increased.
It was this special ability that put men far ahead of other living creatures in the struggle for existence. 47) He mastered darkness first with dim lights and later with brighter and brighter lamps, until he can now make for himself so dazzling a light with an are lamp that, like the sun, it is too p for his naked eyes.
48) Man found that his own muscles were too weak for the work which he wanted to do; he explored many other forms of power until now he has his hands on the ultimate source of physical energy, the nuclear power. From man’s earliest days the flight of birds has raised his wonder and desire. Why should he not fly as they did Then he began to experiment. At last he learnt how to make the right machines to carry him through the air. Now he can fly faster than sound. Already he has plans for conquering space, and a series of experiments has been completed. 49) It will not be long now before man takes a giant step away from his planet and visits the moon, learning what it is like to have no weight to his body, no upward direction and no downward.
Man, always a wanderer, has to overcome the difficulty of adapting himself to different climates. 50) Fortunately, in spite of having no. thick skin or warm fur to protect him, he is peculiarly p compared with other living creatures, most of whom are unable to live far outside the region that suits them best.
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