〜てしまいます
Finish it off — or oh no
Do it all the way to the end. The plate is empty.
たべてしまいました
An accident, a mistake, something you can't take back.
わすれてしまいました
てしまう squeezes to ちゃう, でしまう to じゃう. This is what you hear.
たべちゃった
かぎを わすれて しまいました。
わたしの かぎを つかって ください。
ぜんぶ してしまう
The third and last thing Phase O bolts onto the て-form. Sense one: 〜てしまいます means you did it all the way to the end. It's the difference between “I ate it” and “I ate it all up”. 🔊 Tap to hear.
て-form ＋ しまいます, sense one: finish it off, all the way to the end. It's the difference between “I ate it” and “I ate it all up”. The plate is empty, the book is closed, the homework is done.
あ！ しまった
Sense two, and the one you'll meet most often: something happened that you didn't want. A mistake, an accident, something you can't undo. The grammar is identical — only the feeling changes, and the situation makes it obvious which is meant. 🔊 Tap to hear.
Sense two, and the one you'll hear most: oh no. Something happened that you didn't want — a mistake, an accident, something you can't take back. The grammar hasn't changed at all; only the feeling has. Context tells you which sense is in play, and with words like わすれる or おとす it's obvious.
〜ちゃう・〜じゃう
Now the payoff. In conversation almost nobody says 〜てしまう in full — it squeezes down, and the short form is everywhere in anime and everyday speech. Follow the て or で of your て-form and you'll never pick the wrong one.
Past tense is ちゃった／じゃった — たべちゃった, わすれちゃった. Use these with friends and keep 〜てしまいます for polite situations.
That's the phase. The wrap-up test lives on its own page now — take it whenever you're ready.