The cave-making recipe calls for a steady emission of volcanic gas and heat, a heavy annual snowfall at an elevation high enough to keep it from melting during the summer.
洞穴的形成需要火山气体和热量的稳定释放，海拔高到足以防止每年的大量降雪在夏季融化。
2
He says it will have a highmelting point.
他认为硅的熔点非常高。
3
So strong bonds means highmelting points and boiling points.