Hydrogen is a useful gas for balloons. It is lighter than air.

氢气对于气球来说是一种有用的气体, 它比空气轻.

英汉非文学 - 科学史

Balloons are aerostats, which means that are lighter than air when inflated.

气球是轻飞行器,也就是说,充气后, 它们会比空气轻.

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Lighter than air, a song or so It'seems.

看似一首歌,或轻甚空气.

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We tell the story of lighter - than - air balloons.

我们将播讲有关人类乘坐轻气球飞行的故事.

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Hydrogen is much lighter than air.

氢比空气轻得多.

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Being both lighter than air and nonflammable, helium is used to inflate balloons and airships.

由于既比空气轻又不可燃, 氦用作充气球和飞艇.

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In nature, lighter - than - air volcanic lava traps bubbles of various sizes as the molten rock cools.

自然界中, 比空气还轻的各种火山灰在冷却过程中变为海底火山岩.

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