1. Words that are used to describe space, time & location & determining the relation between nouns & pronouns. Examples of simple prepositions are on, over, at, under, by, for, in, off, over, and under. example :
a. She lost her ring in the pool.
b. We are running in the park today.
2. When two prepositions are combined to form a single word are called compound prepositions. Example – above, across, inside, within, beyond. example :
a. He likes to play inside.
b. Her apartment is just above mine.