なくてはならない
Must do, Have to do
Structure
Verb［
Explanation
While it may look like てはならない, the grammar point なくてはならない has a completely different function. It creates a double negative, which expresses a strong obligation that something 'must be done' or that one 'has to do (A)'.
The common English translation is 'must do', but the literal meaning is closer to 'it won't do if (A) is not done'. This double negative can be a source of confusion for many students. The final part, ならない, means 'is not acceptable' or 'will not do', and is derived from the negative form of the verb なる (to become).
To construct this grammar, first, take the negative form of a verb (the ない-form). Next, change the final い in ない to く, which is its conjunctive form. Then, add て, followed by the particle は, and finally finish with ならない.
- 明日までにこのレポートを終わらせなくてはならないです。I have to finish this report by tomorrow.
- 田中さんは会議に出席しなくてはならないです。Mr. Tanaka must attend the meeting.
- 健康のために、毎日野菜を食べなくてはならないです。For my health, I have to eat vegetables every day.
Of the common endings for this structure, ならない is the most formal. It is primarily used in official writing and formal speech. The alternatives, いけない (the most common) and だめ (the most casual), are widely used in everyday situations.
- そろそろ空港に向かわなくてはいけない。I have to head to the airport soon.
- 薬を飲む前に、ご飯を食べなくてはダメ。You have to eat a meal before taking the medicine.
Caution
In casual conversation, ては is often contracted to ちゃ for easier pronunciation. While なくちゃ could technically be followed by ならない, this pairing is rare because the casual feel of なくちゃ clashes with the formal tone of ならない. It is far more common to pair なくちゃ with いけない or だめ.
- ああ、もうこんな時間か。そろそろ寝なくちゃならない。Oh, it's already so late. I really must get to sleep.
- 電車に乗る前に、切符を買わなくちゃいけない。I gotta buy a ticket before I get on the train.
- 映画が始まるよ。早く行かなくちゃだめだよ。The movie's starting! We gotta go now.
These informal contractions are very much like saying 'gotta' in English.
Examples
部屋を掃除しなくてはならない。
I have to clean my room.
明日までに、レポートを出さなくてはならない。
I have to submit the report by tomorrow.
もう終電の時間だ！急いで帰らなくてはならない。
It's already time for the last train! I have to hurry home.
空港でパスポートを見せなくてはならない。
You must show your passport at the airport.
彼に真実を話さなくてはならないよ。
You have to tell him the truth.
家に入る時、靴を脱がなくてはならない。
You must take off your shoes when entering a house.
この町では、ゴミを分別しなくてはならない。
In this town, you must sort your trash.
パスワードを忘れたので、リセットしなくてはならない。
I forgot my password, so I have to reset it.
国民は税金を払わなくてはならない。
Citizens must pay taxes.
そのレストランに行く前に、予約をしなくてはならない。
You have to make a reservation before you go to that restaurant.
生きているうちに、一度は富士山に登らなくてはならない。
While I'm alive, I must climb Mt. Fuji at least once.
明日は朝から会議があります。早く起きなくてはなりません。
I have a meeting tomorrow morning. I have to get up early.