Of and Off
The word of is a proposition that is used to indicate a relationship between two separate, but connected things and people.
The word off is, and adjective, an adverb, a noun, a proposition, and a verb, which indicates separation or disconnection.
How to remember which to use in a sentence.
If you are referring to relationship between things and/or people, it’s of you should use.
Whereas off is the opposite of on.
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