Plain past: Verb た JLPT N5
The plain (casual) past tense, and the base many later patterns attach to.
Formation
Formed exactly like the て-form, with た/だ instead of て/で: 書いて -> 書いた, 飲んで -> 飲んだ, 行って -> 行った, 食べて -> 食べた.
Explanation
The た-form follows the same euphony (音便) as the て-form, so once the て-form is known the past is the same change with た/だ. It is the casual equivalent of ました and the base for ことがある, たら, たり and more.