Prepositions help explain the relationship between things. This is important since English lacks some of the cases used in other languages like Russian.A preposition must be followed by a noun (for example, "The owl is on the branch.")
Prepositions can include prepositions of time, space, and movement.
Get used to using prepositions as a way of conveying meaning. Some of these following exercises may help you in this respect.See Prepositional Phrases.