什么是水力粗糙管?
参考答案:
若近壁层流层的厚度小于绝对粗糙度,这种管子在水力学上称为水力粗糙管。
基础训练篇(18)
There were once a goat and a donkey 1. lived on a farm. The donkey worked the hardest so the farmer fed it the most 2. . Sometimes the donkey was given more food 3. it could eat. This made the goat so jealous 4. it began plotting against(谋划对付) the donkey. “Hey, donkey,” the goat said one day. ”I think you do too much work on this farm. You carry such heavy things from morning to night. Why don’t you pretend 5. (get) sick so you can take a day 6. ?” The donkey thought the goat had a great idea. So the next morning, the donkey lay in the stable(畜栏) on its side with its eyes 7. (close). Right away, the farmer called in a doctor. 8. looking at the donkey, the doctor said it needed a special medicine made 9. the heart of a goat. So the farmer killed 10. goat and gave the donkey medicine made from its heart.
不属于报表包含的要素是()。
A、报表的数据
B、报表格式
C、填写人及日期
D、编码及编号