资料来源 : pyDict

前寒武纪,前寒武层

资料来源 : WordNet®

Precambrian
     n : the eon following the Hadean time and preceding the
         Phanerozoic eon; from about 3,800 million years ago until
         544 million years ago [syn: {Precambrian eon}, {Precambrian
         aeon}, {Precambrian period}]