We can use fall as a noun or a verb. It means:
1. suddenly go down onto the ground or towards the ground unintentionally or accidentally
2. come down from a higher position|
Fall as a noun or a verb.
Fall does not need an object:
● Mrs McGrath had a terrible fall yesterday. She’s in a hospital now. (noun)
● Four trees fell in the storm. (verb)
Fall down is a phrasal verb.
We use it when something falls to the ground from its normal position:
● The picture keeps falling down. (from the wall to the ground)
● He slipped and fell down.
We use fall, not fall down when trees drop their leaves during the autumn:
● As autumn came and the leaves fell from the trees, she began to feel sad.
Not: … the leaves fell down …
We can’t use fall down to mean ‘come down from a higher position’:
● House prices have fallen a lot this year.
Not: House prices have fallen down a lot …