驾驶机动车在山区道路因故障停车需要注意什么？
A．选择下坡路段停放
B．选择上坡路段停放
C．选择平缓路段停放
D．选择坡顶位置停放
参考答案：C
慢性增生性牙髓炎时探诊深龋洞可发现( )
A．洞底硬，无疼痛感B．洞内探到穿髓孔，感疼痛C．洞内有红色肉芽组织增生D．洞底有大量软化腐质E．洞底穿孔达根分歧
Which of the following statements about the economic rent to a natural resource is most accurate（）
A. The entire payment for a non-renewable natural resource is economic rent.
B. A non-renewable natural resource earns economic rent only if demand for the resource is perfectly inelastic.
C. The entire payment for a renewable natural resource is economic rent.
