Prepositions are of five different kinds:

1.    Simple prepositions
2.    Compound prepositions
3.    Double prepositions
4.    Participle prepositions
5.    Phrase prepositions

Simple Prepositions

Simple prepositions are words like in, on, at, about, over, under, off, of, for, to etc.

She sat on the sofa.
He is going to the market.
He fell off the ladder.
There is some water in the bottle.
She is about seven.
They sat around the table.
The cat was hiding under the bed.

Compound prepositions

Compound prepositions are words like without, within, inside, outside, into, beneath, below, behind, between etc.

He fell into the river.
She sat between her kids.
He sat beside her.
There is nothing inside the jar.
The teacher stood behind the desk.
The boy ran across the road.

Double prepositions

Double prepositions are words like outside of, out of, from behind, from beneath etc.

Suddenly he emerged from behind the curtain.
He walked out of the compound.

Participle prepositions
Participle prepositions are words like concerning, notwithstanding, pending, considering etc.

There was little chance of success, notwithstanding they decided to go ahead.
You did the job well, considering your age and inexperience.

Phrase prepositions
Phrase prepositions are phrases like because of, by means of, with regard to, on behalf of, instead of, on account of, in opposition to, for the sake of etc.

I am standing here on behalf of my friends and colleagues.
The match was cancelled because of the rain.
He succeeded by means of perseverance.

Prepositions and Adverbs

There are some words which can be used both as prepositions and as adverbs. If a word is used as a preposition it will have a noun or pronoun as its object. Adverbs, on the other hand, do not have objects. They are used to modify a verb, adjective or another adverb.

Compare:

She sat in the armchair. (In – preposition; armchair – object)
Please come in. (In – adverb; no object)
He stood before me. (Before – preposition; object – me)
I have seen him before. (Before – adverb; no object)
She put the book on the table. (On – preposition; object – the table)
Let’s move on. (On – adverb; no object)
He will return after a month. (After – preposition; object – a month)
He came soon after. (After – adverb; no object)