Tense is a form of a verb that expresses a particular period of time in which an action takes place. When writing, it is important that the tense of the actions agree with the context of the writing.
In the following examples, the verb has been italicized, and the tense has been explained:
When the show ended, the audience leaves the theater.
The sentence begins in past tense with “ended,” so the present tense verb, “leaves” does not agree with the sentence.
When the show ended, the audience left the theater.
When I go to the store, I bought lots of groceries.
The sentence begins in present tense with “go,” so the past tense verb, “bought” does not agree with the sentence.
When I go to the store, I buy lots of groceries.
Writers need to concern themselves with tense. It is important throughout writing. An idea that begins in a certain tense must remain in that tense until a new idea begins. Generally, the same tense is used throughout an essay or short story.