1.N-UNCOUNT 不可数名词乙炔，电石气（一种无色可燃气体，有高热烈焰，常用于灯具照明、切割和焊接金属等） Acetylene is a colourless gas which burns with a very hot bright flame. It is often used in lamps and for cutting and welding metal.

【搭配模式】：oft N n