This document discusses the proper use of prepositions in the English language through examples of sentences containing ambiguous prepositions. It explores the different prepositions that can be used in various contexts and phrases, examining how subtle changes in prepositions can alter the meaning of sentences. Key prepositions discussed include in, at, of, for, to, with, by, from, on, about, against, among, over, of, into, onto and thereof/therefor/therefrom.