fall over、fall down都是倒下、倒塌的意思. 例:The toddler tried to walk but kept falling down.那小孩学着走路但老是跌跤. She fell over and broke her leg.她跌倒後摔折了腿. fall off是向下倾斜或者数量或质量下降的意思. 例:Beyond the hill,the land falls off sharply towards the river.山那边地面呈陡坡向河边倾斜. Attendance at my lectures has fallen off considerably.听我讲课的人已大大减少了. 再问: 谢谢你