fell off,fell down,fell over有什么区别?

fell off
落下,衰减,下降
例句:
To my great amusement his false beard fell off.
使我感到极其好笑的是他的假胡子掉下来了.
I need a new bicycle lamp my old one fell off and broke.
我需要一个新的自行车车灯--旧的摔破了.
She fell off her bike and got a nasty knock.
她从自行车上摔下来,摔得很重.
fall down
跌倒,失败
例句:
How was it possible to fall down from the third floor without being hurt?
从三楼掉下而没有受伤,这怎么可能呢?
You must watch your step so as not to fall down.
你必须留心脚下才不会跌下去.
The council's answer to the population expansion is to build high block of flats,but that's where the plan falls down.
会议对人口膨胀问题的答复是建高层建筑,但这正是计划的失败之处.
fell over
翻倒,摔倒
fall over的过去式
例句:
Her hair fell over her shoulders in a mass of curls.
她的鬈发披在肩上.
He fell over on the ice.
他摔倒在冰上.
She fell over and broke her leg.
她跌倒后摔折了腿.