玻璃纤维复合板风管内壁采用涂层材料时，其材料应符合什么卫生规定？
参考答案：应符合对人体无害的卫生原则。
There’s no ________ from my bedroom window except for some factory chimneys.
A．view
B．scene
C．sight
D．look
He is the most intrepid explorer in the present century.
A. successful B. fearlessC. reliable D. fearsome
