Whx didn't Tom come to school?—He _________ and hurt his leg.A.fell downB.felk offC.falls down我知道选B,我想问为什么不选A

Whx didn't Tom come to school?—He _________ and hurt his leg.A.fell downB.felk offC.falls down我知道选B,我想问为什么不选A
Whx didn't Tom come to school?
—He _________ and hurt his leg.
A.fell down
B.felk off
C.falls down
我知道选B,我想问为什么不选A

Whx didn't Tom come to school?—He _________ and hurt his leg.A.fell downB.felk offC.falls down我知道选B,我想问为什么不选A
fall down强调的是“滑倒、倒下”,后接宾语时应加上介词from
男孩重重地撞在树上,结果自己倒下了.
fall off强调的是“跌落、从……掉下来”,后直接接宾语

就是选A 。
答案错了吧。