A preposition is a word that links a noun, pronoun or noun phrase to some other part of the sentence. For example the preposition on can be used to: express a surface of something:1. I put a plate on the kitchen table2. The paper is on the floor.used to specify dates:1. The train comes on Wednesdays2. I was born on the 30th day of December 1906used to indicate a device or machine such as a phone or computer:1. She is on the phone right now2. He has been on the computer since morning3. I watch sports on TV every Saturday.
english grammer preposition