元古代 yuángǔdài Proterozoic Era Definitions Defs Origin Strokes Stroke Words Sentences Sents 元古代 yuángǔdài Proterozoic Era Proterozoic geological era, occurring approximately 2500 to 541 million years ago Frequency Written text 0.172 per million Sources Frequency data BCC Corpus (BLCU)
元古代 yuángǔdài Proterozoic Era Proterozoic geological era, occurring approximately 2500 to 541 million years ago Frequency Written text 0.172 per million Sources Frequency data BCC Corpus (BLCU)
