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Must not / may not
Definition
The grammar pattern "〜てはいけない" is used to express a strict prohibition or a rule that must not be broken. It is stronger than the polite request "〜ないでください" and implies that the action is not allowed under any circumstances. This pattern is often used in situations where a rule or regulation must be followed, and breaking it would have serious consequences.
Structure
| Form | Pattern | Example |
|---|---|---|
| Te-form of a verb | Verb te-form はいけない | 食べる te-form はいけない |
| Polite te-form of a verb | Verb polite te-form はいけません | 食べる polite te-form はいけません |
| Negative te-form of a verb | Verb negative te-form はいけない | 食べない te-form はいけない |
Examples
この部屋でたばこを吸うのは禁止です。
Kono heya de tabako o suu no wa kinshi desu.
Smoking in this room is prohibited.
この部屋で (in this room), たばこを吸う (smoking), は (is), 禁止です (prohibited)
試験中、携帯電話を出してはいけません。
Shiken-chū, keitai denwa o dashite haike nai desu.
You must not take out your cell phone during the exam.
試験中 (during the exam), 携帯電話を出して (taking out your cell phone), はいけません (must not)
お母さん：「夜遅くまでゲームをすると体が疲れるよ。」
Okaasan:「Yoru osoku made gēmu o suru to karada ga tsukareru yo."
Mother: "If you play games until late at night, you'll get tired."
夜遅くまで (until late at night), ゲームを (playing games), すると (if), 体が疲れる (get tired)
この学校では、自転車を学校内で走らせることは禁止です。
Kono gakkō de wa, jidōsha o gakkō nai de hashiraseru koto wa kinshi desu.
Riding a bicycle inside the school is prohibited.
この学校では (in this school), 自転車を (riding a bicycle), 学校内で (inside the school), 走らせる (riding), ことは (is), 禁止です (prohibited)
このビルでは、車を駐車する場所が少ないため、車を駐車することは禁止しています。
Kono biru de wa, kuruma o chaku-sa suru basho ga sukunai tame, kuruma o chaku-sa suru koto wa kinshi shite imasu.
There are not enough parking spaces in this building, so parking a car is prohibited.
このビルでは (in this building), 車を (parking a car), 駐車する (parking), 場所が (spaces), 少ない (few), ため (because), 車を (parking a car), 駐車する (parking), ことは (is), 禁止しています (prohibited)
Context
The grammar pattern "〜てはいけない" is used to express a strict prohibition or a rule that must not be broken. It is stronger than the polite request "〜ないでください" and implies that the action is not allowed under any circumstances. This pattern is often used in situations where a rule or regulation must be followed, and breaking it would have serious consequences.
Watch out
〜ないでください is used to make a polite request, whereas "〜てはいけない" is used to express a strict prohibition or a rule that must not be broken.
〜てもいい is used to express permission or allowance, whereas "〜てはいけない" is used to express a strict prohibition or a rule that must not be broken.
〜てはいけない is used to express a strict prohibition or a rule that must not be broken, whereas "〜ないでください" is used to make a polite request.
Strategy
When using "〜てはいけない" in the JLPT exam, make sure to use it to express a strict prohibition or a rule that must not be broken. Avoid confusing it with "〜ないでください" or "〜てもいい". Practice using it in different contexts to improve your understanding of its usage.
Related
In context
Worked examples drawn from JLPT N5 test-style questions. Each sentence shows 〜てはいけない used correctly, with a brief note on what the pattern is doing.
この部屋でたばこを吸ってはいけません。
Pattern used: 吸ってはいけません
A rule prohibiting smoking uses 〜てはいけません. 〜ないでください is a softer request, while 〜てもいいです grants permission.
試験中、辞書を使ってはいけません。
Pattern used: 使ってはいけません
During an exam, using a dictionary is strictly prohibited. 〜てはいけません expresses this rule. 〜てもいいです would mean it is allowed.
お母さん：「夜遅くまでゲームをしてはいけないよ。」
Pattern used: してはいけない
A mother telling her child a rule uses the casual form 〜てはいけない (not いけません). This is a prohibition, not a polite request.
Interactive
この部屋でたばこを______。
Adaptive practice
Our adaptive engine will quiz you on this grammar pattern and track your progress toward mastery.