请结合给定资料，分析如何把握好文化遗产保护与产业开发之间的关系。 要求：准确、全面

With international ______ and education exchanges increasing every year, the number of Chinese students studying abroad has increased rapidly.

A．cooperation

B．competition

C．construction

D．conflict

眼和眼眶通常扫描的层厚是（）

A.2mm

B.5mm

C.10mm

D.15mm

E.20mm

请简述目前燃气供热锅炉房要求制订的几项制度？

单斗挖土机按工作装置分为哪几种类型？其各自特点及适用范围如何？