固定碳
参考答案：
燃料中挥发物分离燃烧后，余下碳和灰分组成的固体物，其中的碳分为固定碳。
How should signal flares be used after you have abandoned ship and are adrift in a liferaft?（）.
A.Immediately use all the signals at once
B.Use all the signals during the first night
C.Employ a signal every hour after abandoning ship until they are gone
D.Use them only when you are aware of a ship or plane in the area
在断面较小，岩石坚硬的小断面巷道和使用高威力炸药时，应用（）小直径药卷。
A.15～20mm
B.25～30mm
C.38～45mm
