How to emphasize that an action has been completed OR will be completed in the future.
~てしまいました
~てしまいます
Note: Casual form would be “Verb stem + ちゃった”
What can be used to demonstrate regret?
- Note: In obvious situations only
~てしまいました
車の鍵をなくしてしまいました!
- I lost my car key! (How sad)