下列说法中正确的是（） A.在实际流体中，作用在流体微团表面的

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问题单项选择题

下列说法中正确的是（）

A.在实际流体中，作用在流体微团表面的法向应力即为流体动压强

B.若液体运动轨迹是一个圆，则应为有旋流；若液体运动轨迹是直线，则应是无旋流

C.涡通量和速度环量都能表征旋涡强度

D.涡量即速度矢量旋度的两倍，也是一个矢量

答案

参考答案：C

听力题

单词拼写根据句子意思和所给首字母写出所缺单词。（每小题1分，满分10分）

小题1: It is necessary to make a good i_________.

小题2: She keeps f_______ by swimming every morning.

小题3:He is not here right now. Can I take a m_________?

小题4: Lawyers are p_______ about 50 dollars an hour.

小题5: They did arrive together, but I think they left s__________.

小题6: I’m giving you a final w_________ —don’t be late again.

小题7: S_______ the bottle before taking the medicine.

小题8: When she retired, she did a lot of v__________ work for the Red Cross.

小题9:Olaf is one of the most interesting c__________ in the film, Frozen（冰雪奇缘）.

小题10:Please don't laugh - I'm being s____________.

问答题简答题

判定二极管好坏的简单方法？