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问题 选择题

In order to reduce the increasing prices of vegetables , the toll(过路费)           if a truck carrying them passes through a toll station .

A．cancels

B．is cancelled

C．was cancelled

D．had been cancelled

答案

答案：B

考察时态及语态。句意：为了降低蔬菜正在升高的价格，当通过收费站时运菜的卡车的过路费被取消了。描述的是现在的一种客观状态，过路费是动作的对象，故用被动语态，一般现在时态，选B。

选择题

生活中常见的三种物质：①醋酸，②肥皂水，③食盐水．醋酸能使紫色的石蕊试液变红，肥皂水使酚酞试液变红，食盐水的pH=7．它们的pH由小到大排列，正确的是（　　）

A．①②③

B．①③②

C．②①③

D．③①②
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问答题

Man first appeared on 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 arc 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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