Must not do with 〜てはだめだ
Grammar: Prohibition » 〜てはだめだ
Saying one must not perform an action is conveyed by a verb in its て form, the particle は, and the adjective だめ (“cannot”, “must not”, “not allowed”), ending in だ.
Related Grammar
- Should not do with 〜てはいけない
- Used to discourage (rather than prohibit) an action.
- Must not do with 〜べからず
- An old-fashioned way to strongly forbid an action.
Examples
Don't be found with 〜てはだめだ
While telling ghost stories at night, Rize relays the tale from her childhood, of a frightened servant walking home one night. Rize says the culprit was her, practicing sneaking around and crawling through the bushes.
- 「バラしちゃだめじゃん！！」
- “Don't be found!!”
Note that じゃん is a short form of じゃない, the negative of だ.
Don't grow bigger with 〜てはだめだ
On the topic of Chino outgrowing Cocoa, Cocoa is fine with it until she learns Chino won’t be like a doting big sister to her.
- ココア:
- 「チノちゃんは大きくなっちゃだめ！」
- “You mustn't become bigger.”
Note that だ has been dropped from the expression here.
Don't leave your vegetables 〜てはだめだ
During breakfast, Cocoa sees Chino avoiding the vegetable on her plate.
- ココア:
- 「あっ チノちゃんアスパラ残しちゃだめだよ」
- “Ah, Chino, you mustn't leave your asparagus.”
