从摔下来的英文表达是 "fall off"。
这个短语的来源可能源于动词 "fall"，它的意思是 "掉下，跌倒"。"off" 是介词，表示"离开"或 "从...中离开"的意思。
例句1:
The horse's rider fell off and broke his leg.
(马的骑手摔下来了，断了腿。)
例句2:
The apple fell off the tree.
(苹果从树上掉下来了。)
例句3:
He fell off the ladder while painting the house.
(他在粉刷房子时摔下了梯子。)