超新星残骸以重元素填充宇宙空间，压缩星际气体促进新恒星的形成，因而在星体演化过程中扮演重要角色。
Supernova remnants play an important role in stellar evolution by enriching space with heavy elements, and triggering new star formation by compressing interstellar gas.
液体不像气体，它难以压缩，因为实际上分子之间并没有空间。
Unlike gases, liquids are difficult to compress because there is practically no free space between molecules.
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