Simplify the following text for a Grade 4 native English-speaking person.
Original: A past tense ( abbreviated ) is a grammatical tense that places an action or situation in the past of the current moment ( in an absolute tense system ) , or prior to some other event , whether that is past , present , or future ( in a relative tense system ) .
Simplified: The simple past tense is used when telling a story . Different verbs change in different ways to make the past tense .