良莠不齐 liángyǒu-bùqí

[grain or chaff;the good and the bad are intermingled; sheep and goats; there are bad as well as good people in the group; there are weeds among seedlings; thread and thrum] 莠:狗尾草,比喻品质坏的人。比喻好人坏人混在一起

无如众生愚贤不等,也就如五谷良莠不齐。——清· 文康《儿女英雄传》

• 指好人坏人都有，混杂在一起。莠，狗尾草。比喻坏人。
  

  《镜花缘》第六八回：“此时臣国西宫之患虽除，无如族人甚众，良莠不齐，每每心怀异志，祸起萧墙。”

  郑观应 《盛世危言·训俗》：“至於海外贸易工作之商民，不下数千百万，五方杂处，良莠不齐。”