What is single preposition?

A single preposition is simply one preposition used alone, without any other words modifying it.

Here are some examples of single prepositions:

* on the table

* in the box

* at the store

* for you

* with friends

* to school

Compare this to a prepositional phrase:

A prepositional phrase includes the preposition and its object (the noun or pronoun that the preposition relates to).

* on the table (preposition: on, object: table)

* in the box (preposition: in, object: box)

* at the store (preposition: at, object: store)

So, "on" is a single preposition, while "on the table" is a prepositional phrase.