a wolf in sheep's clothing
披着羊皮的狼
1.Mrs.Martin trusted the lawyer until she realized that he was a wolf in sheep's clothing
马丁太太很信任那个律师,直到她发现他是个披着羊皮的狼。
2.One who teaches morality and practises immorality is a wolf in lamb's skine.
那种口口声声喊着道德,但又做着不道德的事的人就像是披着羊皮的狼。