人体合成尿素的主要器官是()。
A.脑
B.肌组织
C.肾
D.肝
E.心
参考答案:D
— "Amy, I called you yesterday evening, but nobody answered the phone.
—Oh, I _________a walk with my mother at that time. [ ]
A. take
B. took
C. am taking
D. was taking
05Pa·s的油品在φ112mm×6mm的圆管内流动,管截面上的速度分布可表达为 uy=20y-200y2 式中:r为管截面上任一点到管壁面的径向距离,m;ur为y点处的速度,m/s。 则油品在管内的流型为( )。
A.(滞流
B.(湍流
C.(过渡流
D.(不确定