谁都
shéi dōu
Expressing "every" with question words
Any question word followed by 都 stops asking and starts meaning "every".
Question Word + 都 / 也 + Predicate
How it works
谁都可以进 — anyone can come in. 哪儿都行 — anywhere is fine. 什么时候都可以 — any time works.
Negated, the same shape means "nobody/nowhere/nothing": 谁都不知道.
This generalises the 什么都 pattern from HSK 2 across the whole set of question words.
Examples
shéi dōu kě yǐ jìn
谁都可以进。
Anyone can come in.
wǒ nǎr dōu bù xiǎng qù
我哪儿都不想去。
I don't want to go anywhere.
shén me shí hou dōu kě yǐ
什么时候都可以。
Any time is fine.