N4 · Structured courses

Te Shimau: Completion and Regret

Learn てしまう for complete actions and expressing regret about something irreversible. This lesson combines form, context, examples, common mistakes, and practice so you can use the pattern in real communication.

12 minNihongo Hub Editorial TeamPublished 2026-06-06Updated 2026-06-06

Learning objectives

  • Lesson goals: Learn てしまう for complete actions and expressing regret about something irreversible.
  • Form and connection: [Verb te-form] しまう
  • Nuance in real use: てしまう captures a quality of time — some things once done cannot be undone. Whether completion or regret, it marks those "it's already happened" moments.

Form and connection

[Verb te-form] しまう

Core Explanation

Learn てしまう for complete actions and expressing regret about something irreversible.

Cultural Note

てしまう captures a quality of time — some things once done cannot be undone. Whether completion or regret, it marks those "it's already happened" moments.

Practical examples

I finished all my homework.
I (accidentally) lost my wallet.
I ate all the cake.
I missed the train.

Common pitfalls

Build the base form before adding the pattern

Complete the required conjugation first. Do not keep polite and plain endings at the same time.

Match politeness to the situation

The examples are reliable starting points; relationships and context can still change the most natural wording.

Practice and answers

1. Write the connection formula for this lesson.
Show answer[Verb te-form] しまう
2. Explain the meaning of the first example.
Show answerI finished all my homework.
3. Rewrite the final example using this lesson pattern.
Show answer電車でんしゃに乗のり遅おくれてしまいました。 ([Verb te-form] しまう)

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