(2009年)正常工作条件下的薄壁小孔口与圆柱形外管嘴，直径d相等，作用水头H相等，则孔口流量Q1和孔口收缩断面流速V1与管嘴流量Q2和管嘴出口流速V2的关系是( )。
A. V1＜V2，Q1＜Q2
B. V1＜V2，Q1＞Q2
C. V1＞V2，Q1＜Q2
D. V1＞V2，Q1＞Q2
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Questions 12 to 15 are based on the conversation you have just heard.
A. The curiosity to know the causes of people"s behavior.
B. The factors that influence people"s decision.
C. The motives for people"s behavior.
D. The consequences of people"s bad behavior.
(2006年) 在附壁紊流中，黏性底层厚度δ比绝对粗糙高度△大得多的壁面称为( )。
A. 水力光滑面
B. 水力过渡粗糙面
C. 水力粗糙面
D. 以上答案均不对
Questions 9 to 11 are based on the conversation you have just heard.
A. Their new assignment for next week.
B. Their creative writing professor.
C. A really strange book by some French guy.
D. A great English author.
(2006年)边界层分离不会( )。
A. 产生漩涡
B. 减少摩擦阻力
C. 产生压强阻力
D. 增加能量损失
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