なくてはいけない (Must do)
Must do, Have to do
JLPT N5
Pattern
Verb (ない-form → なくて) + はいけない
How it works
なくてはいけない is a double negative meaning “must do”: literally “not doing is not allowed”. Make the ない-form, change ない to なくて, and add はいけない (polite: いけません). It often expresses personal or situational obligation.
Examples
- あしたは はやく おきなくては いけません。I have to get up early tomorrow.
- くすりを 飲まなくては いけません。I must take my medicine.
Related grammar
Further reading
Bunpro N5 · Lesson 9Put your practice together
Work through a complete paper at your own pace or choose a timed mock exam. No account is needed to begin.