人口自然结构。
参考答案：
是指人口各自然属性之间的比例关系。主要包括人口种族构成、人口性别构成和人口年龄构成。
You are the project manager for a complicated construction project which involves building highways in the whole state of North Carolina. You have several groups working with you in the project. To plan resources for this project, you should preferably use a/an ______ .
A．staffing pool description
B．staffing management plan
C．responsibility assignment matrix
D．organization matrix
旋转阳极X线管阳极倾角一般在
A．5°～8°
B．15°～28°
C．25°～28°
D．5°～28°
E．12°～19°
