state of matter

例句：

1. 1. The state of the matter is not good.
   情况并不好。
2. 2. The scientists are studying the state of matter in space.
   科学家们正在研究太空中的物质状态。
3. 3. The state of matter can change when a substance is heated or cooled.
   物质状态在物质被加热或冷却时会发生变化。