a wolf in sheep's clothing

　　a wolf in sheep's clothing批着羊皮的狼;貌善心恶的人

　　耶稣在加利利一带传道布教，收了很多信徒。有一天，他对门徒说:"Beware of false prophets,which come to you in sheep's clothing,but inwardly they are ravening wolves""

　　eg:Mrs.Martin trusted the lawyer until she realized that he was a wolf in sheep's clothing