与美国小学生一起学英文第5册 第11期:气体

 　　Gas 气体

　　There are three different kinds of matter. They are solids, liquids and gases. 物质分三种：固体、液体和气体。

　　Gas has no shape, so you can't touch gas. 气体本无形，所以你触摸不到。

　　Gas moves very freely¹. 气体能非常自由地运动。

　　Gas can change into a solid or a liquid when the temperature gets too low. 当温度变得很低时，气体就能变成固体或液体。

　　On the other hand, a solid can change into gas when the temperature gets too high. 反之，当温度变得很高时，固体或液体就能变成气体。

　　Is there a good example of these changes? 有没有这些变化的好例子？

　　Of course, it is dry ice. 当然有，它就是干冰。

1 freely   

adv.自由地，随便地，无拘无束地

参考例句：

• She was unable to keep back her tears,and wept freely.她抑制不住泪水，痛痛快快地哭了起来。
• A liquid flows freely and has no fixed shape.液体能自由流动，无固定形态。