Meaning
Used for prohibition or a strict rule.
Formation
- て form + はいけない: 走ってはいけない
- Colloquial contraction: ては → ちゃ, では → じゃ
When to use it
- Core use
- Must not, is not allowed
Example
ここで走ってはいけない
You must not run here.
Important notes
- Pay attention to the word form before the construction and to the particles around it.
Common mistakes
- Do not translate the pattern word for word; first identify its function in the whole situation.