问题
填空题
一辆汽车沿平直公路运动，以速度v1＝25m/s匀速通过前1/3路程，以速度v2＝50m/s通过其余2/3路程，则汽车在全程中的平均速度是____________m/s。
答案
37.5
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一辆汽车沿平直公路运动，以速度v1＝25m/s匀速通过前1/3路程，以速度v2＝50m/s通过其余2/3路程，则汽车在全程中的平均速度是____________m/s。
37.5
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| Certainly dustmen prefer to be known as "Reuse Collection and Disposal Officers". You may think that this is rather 1 , and it is better to call a spade a spade. But dustmen can be as 2 as people of any other occupation, though we must 3 that their job is not a 4 one in the world. We often take dustmen for granted. Perhaps because they usually come very early in the morning, before most people are 5 .We are likely to forget their 6 .Our dustbins are 7 regularly, but we 8 stop to think about the men who do this. However, it is one of the most important jobs in the world, and when there are no dustmen to 9 the rubbish, the general 10 soon becomes aware that something is wrong. Recently, the dustmen of England went on strike for higher wages. During the first few days it was regarded as a 11 .But when the first two weeks had passed, and the dustbins were overflowing in nearly every backyard in the country, the joke did not seem so 12 any more. 13 the strike continued, people could not 14 the hills of rubbish around their dustbins, and they looked for other places in which to 15 it. Even Leicester Square, in the heart of West End of London, was 16 high with plastic bags full of smelly rubbish. This was a(n) 17 attraction that the people of London were not at all 18 to see. Even when the strike was over, it took several weeks for the country to get cleaned up completely. Perhaps now the English people appreciate the work of 19 dustmen rather more 20 and won't take them for granted any more. | ||||
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