Meaning
Replace non-past ます／ません with ました／ませんでした to talk politely about the past.
Formation
- Verb stem + ました: 行きました, 食べました.
- Verb stem + ませんでした: 行きませんでした, 食べませんでした.
When to use it
- Completed action
- Politely says that an action happened and was completed in the past.
- Action that did not happen
- Says that an action was not performed during the stated past time.
Example
昨日映画を見ました
I watched a film yesterday.
Important notes
- Words such as 昨日 and 先週 make the time explicit, but the ending already marks grammatical past tense.
Common mistakes
- Do not say 行きますでした; the correct single form is 行きました.
- Do not confuse verbal ませんでした with copular ではありませんでした after nouns.