We may normally think of iron as a solid,but if we heat it in a furnace,it will melt and become a liquid,and at very high temperatures it will become a gas.

• 我们通常把铁看成是固体，但如果把它放在熔炉里加热，它就会熔化而变成液体；而在极高温度下，它就会变成气体。