てはいけない
(Te ha ike nai)
Expresses a prohibition that something must not be done.
Connection rules
- +Verb (te-form) + はいけない / はいけません
Examples
1.
危ないですから、ここに入ってはいけません。

Abunai desu kara, koko ni hai te ha ike mase n.
It is dangerous, so you must not enter here.
「Warning at a site」
2.
テスト中に隣の人と話してはいけません。

Tesuto chuu ni tonari no hito to hanashi te ha ike mase n.
You must not talk to the person next to you during the test.
「Teacher during an exam」