How to know the difference between a verb and a noun for example:
We only have "play" how to know if it is a verb or a noun without a sentences or any more word
Without any context it is not a noun or a verb.
It only becomes a verb or a noun in context. By itself, it is just a word with multiple meanings.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.