孪 luán HSK7 twins Definitions Defs Origin Strokes Stroke Words Sentences Sents 孪生 luánshēng twin 孪生兄弟 luánshēngxiōngdì twin brothers 孪生姐妹 luánshēngjiěmèi twin sisters 数字孪生 shùzìluánshēng digital twin Sources Frequency data MTSU Chinese text computingSUBTLEX-CH