问题
问答题 简答题
简述恒定流能量公式适用条件。
答案
参考答案：
1）水流是恒定流。
2）所选取的两个过水断面上的水流应符合渐变流条件，至于两个过水断面之间可以是渐变流，也可以是急变流。
3）在所选取的两个过水断面之间，没有能量的加入和分出，即流量不变。
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简述恒定流能量公式适用条件。
参考答案：
1）水流是恒定流。
2）所选取的两个过水断面上的水流应符合渐变流条件，至于两个过水断面之间可以是渐变流，也可以是急变流。
3）在所选取的两个过水断面之间，没有能量的加入和分出，即流量不变。
阅读短文，根据短文内容完成表格中所缺信息，每空一词。(共l0题，每题l分，计l0分) We all need a healthy environment, but we produce waster every day and it does harm to our environment. Though we are young, we can still do something to help. In fact, even the simplest everyday activities can make a real difference to the environment. Here are some ideas for you to live a green life. Remember these three words; reduce, reuse and recycle（减量、再使用和再循环）. Reduce means “use less”. Don't waste things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think if it is really necessary or maybe the old one will be just as good! When we do buy things, choose local products if possible, and try not to buy too many things from abroad. Reuse means “use again”. Use things for as long as possible. When we buy things, make sure that they last a long time. We should take care of them so that they will last, and we should repair them if we can instead of throwing them away and buying new ones. Don't use a paper cup or a paper bag. It's better to use a china cup and a lunch box because you can use them again. Recycle means “change things into something else”. Although it takes energy to change something into something else, it's better than throwing things away or burning them. Find out what can be recycled in your neighbourhood and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees. Title: 小题1: to Live a Green Life
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