Prepositions are Words that indicate the relationships between various elements within a sentence.
I put (verb) the pen (direct object) under (preposition indicating t. e.g.
I put (verb) the pen (direct object) on (preposition indicating the position of the pen) the table (indirect object). e.g.
The policeman shot (verb) the man (object) with (preposition identifying the man being shot) a knife. e.g.
In formal English, prepositions are almost always followed by objects.
Prepositions are Words that indicate the relationships between various elements within a sentence