水家族有三兄弟：水蒸气、水、冰．在三兄弟中，水蒸气排行老大．它是水的气态，密度最小．水蒸气是空气不可缺少的一部分．正是有它在空气中，我们的皮肤才不会十分干燥．如果没有它，我们就无法生存．水蒸气有一个特性，它在任何温度下都可以生存．因此即使在我国极冷的漠河 The water family has three brothers: water vapor, water and ice. In the three brothers, water vapor ranked the boss. It is the gaseous state of water with the least density. Water vapor is an indispensable part of the air. It is in the air that our skin will not be very dry. Without it, we cannot survive. Water vapor has a characteristic that it can survive at any temperature. So even in our country’s extremely cold Mohe