一点点英语的问题

fall down
倒塌; 跌倒
Many buildings fell down during the earthquake.
在地震中许多楼房倒塌了。
失败
His plans have fallen down.
他的计划失败了
fall off
跌落, 滚落下
When you are learning to ride a bicycle, you often fall off.
初学骑自行车时, 常会从车上掉下来。
突然降低; 向下斜
The land falls off here towards the river.
这儿的地势朝河的方向低了下去。
减少
The number of passengers by this line fell off slightly in January.
一月份这条航线的乘客数量略有减少。
变坏; 恶化
The cooking fell off remarkably.
烹饪质量大大降低。
逐渐消失, 死亡
Words fall off by disuse.
词不用就会成为废词。
不再支持; 叛离
His friends fell off one by one.
他的朋友一个一个地跟他疏远了。
变瘦; (健康、精力等)衰退
He took care to keep the cattle from falling off.
他精心照料着牛群, 不使它们瘦下来。

fall down
KK: [ ]
DJ: [ ]
1. 失败
The plan fell down.
这个计划失败了。

fall off
KK: [ ]
DJ: [ ]
1. (数量)减少
Enrollment has fallen off this