阶层 jiēcéng HSK7 social class Origin Definitions Defs Strokes Stroke Words Sentences Sents 工薪阶层 gōngxīnjiēcéng salaried class 同步数位阶层 tóngbùshùwèijiēcéng SDH synchronous digital hierarchy (SDH), a standardized protocol for high-speed data transmission over fiber optic networks社会阶层 shèhuìjiēcéng social class