adv.狡猾的；秘密地；顽皮地
He's been drinking whiskey on the sly for thirty years. 他暗中偷喝威士忌酒已有三十年了。
Don't trust him, he is a sly old fox. 别相信他，他像老狐狸一样狡猾。
Many people attended the meeting on the sly. 许多人秘密地参加了会议。
He was lurking slyly in the background. 他狡猾地躲在背後活动。
That sly girl managed to get her friend's job. 那个诡诈的女孩设法取得她朋友的工作。
