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Helium
01
氦
a chemical element that is a colorless noble gas which is lighter than air
例子
Helium is a noble gas chemical element with the atomic number 2.
The light isotope of helium, helium-3, is important for its applications in cryogenics and fusion research.
As the air pressure decreased, the helium balloon began to sink toward the ground.
Deep-sea divers breathe a mixture of oxygen and inert gases like helium to prevent nitrogen narcosis at great depths.
The balloon slowly came down to the ground after the helium escaped.
