不能不

bù néng bù gǎn dào wǎn xī

不能不感到惋惜

cannot but express regret

wǒ men bù néng bù tí dào yī xiē lì shǐ shì shí

我们不能不提到一些历史事实。

We cannot very well avoid mentioning certain historical facts.

zhèng dǎng bù néng bù liǎo jiě yī xiē zhèng zhì xiàn shí

政党不能不了解一些政治现实。

The party cannot afford to lose touch with some political realities.

nǐ bù néng bù fù qián jiù guò fù kuǎn chù

你不能不付钱就过付款处。

You can't just go through the checkout without paying.