问题
单项选择题
不可压缩流体恒定总流的连续性方程是()。
A、u1dA1=u2dA2
B、v1A1=v2A2
C、ρ1u1dA1=ρ2u2dA2
D、ρ1v1A1=ρ1v2A2
答案
参考答案:B
不可压缩流体恒定总流的连续性方程是()。
A、u1dA1=u2dA2
B、v1A1=v2A2
C、ρ1u1dA1=ρ2u2dA2
D、ρ1v1A1=ρ1v2A2
参考答案:B
完形填空. | |||
Some people have very good memories and can easily learned quite long poems(诗歌) 1 _ heart. 2 people have poor memories and can only remember thingswhen they have said them 3 and over again. The famous English writer, Charles Dickens, said that he could walk down anylong street in 4 and then told you t'he name of all the shops he had 5 . Many great men of the world have wonderful memories. A good memory is 6 great help in learning a language. Everybody learns 7 0wn language by remembering what he hears when he was a small child. somechildren like those who live in foreign countries with their parents, seems to learn two.languages as 8 as they do one. In school, it is not so easy for people to learn 9 second language because they have very 10 time for it. | |||
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