不能不
HSK 4- Modal verbs
Structure (结构 jiégòu)
Meaning (意思 yìsi)
The double negative structure 不能不 is used to emphasize obligation, meaning "must" or "cannot but do something."
Explanation (解释 jiěshì)
This is a double negation structure that uses 不 twice to create a strong affirmation. 不能不 means "to have no choice but to do something," emphasizing an unavoidable obligation or necessity. It is stronger than 必须 (bìxū) or 得 (děi), and often carries a nuance of slight reluctance or being compelled by circumstances.
Examples (例句 lìjù)(5)
- 快迟到了，我不能不走。繁: 快遲到了，我不能不走。Kuài chídào le, wǒ bùnéng bù zǒu.
It's almost late, I have to go.
- 我朋友病了，我不能不去看他。Wǒ péngyou bìng le, wǒ bùnéng bù qù kàn tā.
My friend is ill, and I cannot but visit him.
- 这是老板的任务，我不能不接受。繁: 這是老闆的任務，我不能不接受。Zhè shì lǎobǎn de rènwu, wǒ bùnéng bù jiēshòu.
This is the boss's task, I cannot refuse to accept it.
- 他说得很有道理，我不能不同意。繁: 他說得很有道理，我不能不同意。Tā shuō de hěn yǒu dàolǐ, wǒ bùnéng bù tóngyì.
He spoke very reasonably, and I couldn't help but agree.
- 为了健康，你不能不运动。繁: 為了健康，你不能不運動。Wèile jiànkāng, nǐ bùnéng bù yùndòng.
For the sake of your health, you cannot avoid exercising.
Common mistakes
- Wrong:我明天有事，不能不来上课。Correct:我明天有事，不能来上课。
`不能不` is a double negative meaning 'must'. To express 'cannot do something', use only `不能`.
- Wrong:我饿了，我不能不吃饭。Correct:我饿了，我得吃饭。
不能不 emphasizes necessity imposed by circumstances. For ordinary situations like eating when hungry, using 得 or 要 is more natural.