Occurrence: Helium comes from natural gas, deposits within Earth, and can be isolated from air.

存在：氦存在于自然大气中，在土壤中沉积，而且能从空气中分离出来。

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Occurrence: Helium comes from natural gas, deposits within Earth, and can be isolated from air.

存在：氦存在于自然大气中，在土壤中沉积，而且能从空气中分离出来。

youdao