几种氡的同位素的放射性气体，是放射性物质衰变的产物。

Any of several radioactive gases that are isotopes of radon and are products of radioactive decay.

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几种氡的同位素的放射性气体，是放射性物质衰变的产物。

Any of several radioactive gases that are isotopes of radon and are products of radioactive decay.

youdao