在潮湿环境操作时，只要戴好绝缘手套和穿好绝缘鞋就可以保证安全。
参考答案：错
一束光自空气垂直直射入玻璃三棱镜AB面，从AC面射出时偏离原方向为θ=15°，棱镜顶角α=30°，求光在该棱镜中的折射率和的传播速度？
The atmosphere in a tank is too lean if it is（）.
A.incapable of supporting combustion because the hydrocarbon content is below the LFL (Lower Flammable Limit)
B.capable of supporting combustion because the hydrocarbon content is above the UFL (Upper Flammable Limit)
C.capable of supporting a fire once started
D.not safe for ballasting
