对于平板，若其宽度为b，长度为l，当边界层中流动为紊流时，对于粗糙表面摩擦阻力随（）变化。
A.A
B.B
C.C
D.D
参考答案：D
具有升颌作用的肌肉()具有使下颌前伸和侧向运动的肌肉()部分肌束起于上颌结节的肌肉()
A．翼内肌
B．翼外肌
C．两者均有
D．两者均无
Which of the following statements best expresses the main idea of the passage?
A.One’s physical appearance can influence our first impression.
B.Our first impression is influenced by the sensitivity of our brain.
C.Stereotypical impressions can be dead wrong.
D.We should adopt mature thinking when getting to know people.
