无所不 Wú suǒ bù 'there is nothing that ... not; everything'
他像是百科全书，可以说他无所不知。 Tā xiàng shì bǎikē quánshū，kěyǐ shuō tā wú suǒ bù zhī.
‘He is like an encyclopedia, we could say he knows everything.’ (lit. 'there is nothing that he doesn't know')
我们是很好的朋友，几乎无所不谈。 Wǒmen shì hěn hǎo de péngyou，jǐhū wú suǒ bù tán.
‘We are really good friends, we talk about almost everything.’ (lit. 'there is almost nothing that we don't talk about')