You eat an apple a day.

Meaning: This sentence conveys the idea of a person regularly consuming one apple each day.

Choice of Words: You is a pronoun that refers to the person being spoken to. Eat is a verb that describes the process of consuming food. An is an indefinite article that refers to one of something. Apple is a noun that refers to a specific type of fruit. A is an indefinite article that refers to one of something. Day is a noun that refers to a 24-hour period.