A preposition is a word that links nouns, pronouns, or phrases to other words in a sentence. It helps to convey relationships of time, place, direction, cause, manner, and instrumentality.
For example, in the sentence ‘The cat is on the roof,’ the word ‘on’ is a preposition that shows the relationship between the cat and the roof. Prepositions are necessary for understanding how elements in a sentence relate to one another.
Common prepositions include ‘in,’ ‘at,’ ‘by,’ ‘with,’ and ‘about.’ They often denote relationships such as location (‘under,’ ‘between’), time (‘during,’ ‘before’), and direction (‘to,’ ‘from’).