てしまうComplete; end up doing
てしまう presents an action as fully completed or as reaching a conclusive result. Depending on the situation, it can also suggest that the result was accidental, regrettable, troublesome, or otherwise noteworthy.
Seeing the action through to its endpoint
For the straightforward completion meaning, this pattern works especially well with an action that has a recognizable endpoint: finishing a book, using something up, completing homework, or putting a task behind you. The focus is not merely that the event happened, but that it was carried all the way through.
この小説は週末に全部読んでしまった。
I finished the whole novel over the weekend.
AnalyzeThe novel provides a clear endpoint, so this is a neutral, emphatic completion rather than a regrettable result.
The surrounding situation supplies the attitude
The same pattern can present a result as unwanted or welcome. Words such as “carelessly,” the nature of the event, and what follows in the sentence tell you how the speaker feels.
うっかり秘密を友達に話してしまった。
I carelessly told a friend the secret.
AnalyzeThe result is clearly unintended because of the adverb and the situation.
心配していた仕事が午前中に片づいてしまって、ほっとした。
The work I had been worried about was all taken care of in the morning, so I felt relieved.
AnalyzeHere the conclusive result is welcome, not regrettable.
Three ways completion can be viewed
もう with a past verb says that something has already happened. A verb followed by 終わる neutrally marks the end of an activity. By contrast, てしまう packages completion into the verb and can also color the completed result with the speaker's reaction.
More examples
宿題は夕食の前にやってしまいます。
I'll finish my homework before dinner.
Analyze会議の資料を一晩で作ってしまった。
I completed the meeting materials in one night.
Analyze電車の中で傘をなくしてしまいました。
I lost my umbrella on the train.
Analyze保存する前にファイルを閉じてしまった。
I closed the file before saving it.
Analyze冷蔵庫にあったジュースを全部飲んでしまった。
I drank all the juice that was in the refrigerator.
Analyze難しい問題も、今日中に解いてしまおう。
Let's get the difficult problems solved today too.
Analyze