〜てはいけません

❗ You must not / You’re not allowed to…

This structure is used to strongly prohibit something. Think of rules, laws, or things that are definitely not okay to do.

🧩 How to Use It

• Structure: Verb (て-form) + はいけません

• ここで写真しゃしんを撮とってはいけません。
  -> You must not take pictures here.
• 授業中じゅぎょうちゅうにスマホを使つかってはいけません。
  -> You must not use your phone during class.

❗Grammar notes:

• In contrast to 〜てもいいです, where the も can be dropped casually (e.g. 食べていいです),
  ➡️ in 〜てはいけません, the は CANNOT be dropped.
  ⛔️ So, you must always say: 〜てはいけません (never ✖️〜ていけません)

💬 Notes:

• Use this expression when you want to clearly say that something is not allowed.
• It’s commonly seen on signs, in schools, offices, or any place where rules are expected.
• When someone asks for permission and you need to deny it, you can use this structure:
  A: トイレに行いってもいいですか。
  (May I go to the bathroom?)
  B: いいえ、行いってはいけません。
  (No, you must not go.)
  ⚠️ Be careful though — this can sound too strict or harsh in casual situations unless you’re in a position of authority (like a teacher or manager). For softer refusals, you’ll learn expressions like 〜ないでください (すみません、今行かないでください) in future lessons.