单选题 15.  The teacher came into the room, with his hands ______ behind his back.
【正确答案】 C
【答案解析】[考点] 非谓语动词
句意为:老师背着手进入教室。“with+done”表被动;“with+doing”表主动。老师的手被背在后面,应用被动形式。