由内侧的面神经垂直段、上方的砧骨窝及外侧的鼓索神经所构成的解剖结构是()
A.后鼓室
B.锥隐窝
C.面神经隐窝
D.Prussak间隙
E.上鼓室前窦
参考答案:C
All of the following are factors that can cause shifts in the demand curve for a resource EXCEPT:()
A. an increase in the supply of the resource.
B. an increase in the resource's productivity.
C. a decrease in the prices of other resources.
造成轨道高低不平顺的因素有哪些?