A Preposition is a word used to express some relation of different things or thoughts from each other. Although overlooked in common speech, prepositional phrases should not be placed at the
end of a question: as:
“Who do I give this to?” This is incorrect; the preposition is at the end of the question.
When corrected, the sentence is: “To whom do I give this?”
Prepositional phrases can be placed at the end of a sentence, however. See the following example:
“She did not sign up for tennis“.
Prepositions are generally placed before a noun or a pronoun: as,
“The paper lies before me on the desk.”
Commonly used English prepositions include: