A thief knows a thief as a wolf knows a wolf.
贼了解贼,正如狼了解狼。
It is a foolish sheep that makes the wolf his confessor.
蠢羊才向狼忏悔。
Don’t trust a goat with the kitchen-garden,or a wolf with sheepfold.
不能请羊管菜园,不能请狼管羊圈。
The wolf has a winning game when the shepherds quarrel.
螳螂捕蝉,黄雀在后。
He that makes himself a sheep shall be eaten by the wolf.
甘心做绵羊,必然喂豺狼。
a wolf in sheep's clothing
披着羊皮的狼, 口蜜腹剑的人
参考资料:http://zhidao.baidu.com/question/17142544.html?fr=qrl3