GRAMMAR DETAIL
〜なくてはいけない
Follows the negative form of a verb to express an obligation or necessity to perform the action. Equivalent constructions built on the same negative condition have the same function.
Examples
パスポートを持って行かなくてはいけない。
I have to take my passport with me.
Words used
出かける前に、窓を閉めなくてはいけない。
I have to close the window before going out.
Words used
明日は六時に起きなくてはいけません。
I have to get up at six tomorrow.
Words used
Study notes
1. Origins, structure, and basic meaning
- Structure: Change a verb's
ないform toなくてand addはいけないto express necessity. - Basic usage:
出かける前に、窓を閉めなくてはいけない。means that the window must be closed before going out.
2. Common pitfalls and similar expressions
- Closing and not closing
閉めなくてはいけないrejects leaving it unclosed and therefore requires closing it.閉めてはいけないprohibits closing itself, giving the opposite meaning.
- Conversational contraction
閉めなくちゃいけないis a conversational form of閉めなくてはいけない. With the ending omitted,閉めなくちゃcan still express obligation or necessity in context.