Two Verb Forms
Present (Formal)
Affirmative - masu/imasu
Negative - masen/imasen
Past (Formal)
Affirmative - mashita/imashita
Negative - masendeshita/imasendeshita
Present (Informal)
Affirmative - Remains unchanged
Negative - anai/nai
Past (Informal)
Affirmative - itta/tta
Negative - kanakatta/ikanakatta