〜てはいけない: must not is a JLPT N4 grammar point. Forbids an action: “you must not…”. Structure: V-て + はいけない／はいけません. This page explains the construction, gives Japanese examples with furigana readings, and links to related grammar points at this level.

〜てはいけない: must not

Structure

V-て + はいけない／はいけません

Explanation

The て form + はいけない states that something is forbidden: とめてはいけません “you must not park (here)”. It is the standard wording of rules and signs. Casual speech shortens it to 〜ちゃいけない／〜ちゃだめ. Contrast with 〜てもいい, which grants permission.

Examples

You must not park your car here.

You must not talk during the exam.

Quiz preview

  • とめては ✓
  • とめても
  • とめると
  • とめないと

V-て + はいけません forbids: “you must not park here”. 〜てもいい would allow it.

  • 話して ✓
  • 話さないで
  • 話さなくて
  • 話した

The pattern needs the て form before はいけません: 話してはいけません.

More N4 grammar points

Potential form (“can do”)〜なければならない: must / have to〜たことがある: have done before〜ながら: while doing〜たら: if / when〜てもいい: permission〜かもしれない: maybe〜と思います: I think that…〜つもりです: to intend to〜たり〜たりする: doing things like…〜てしまう: completely / regrettably

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