都

The single most reliable thing to know about 都 is that its scope goes left, not right. English speakers read 都 as coming before the verb and assume it modifies what follows, but that is backwards. 他们都去 means "they all go" because 都 reaches back to 他们. 他什么都吃 works because 什么 has moved to the front — the question word is topic-fronted into pre-都 position, and 都 then universally quantifies it: "as for what [food], everything, he eats."

This leftward scope is why question words like 什么, 哪儿, 谁, and 怎么 combine so productively with 都: move the question word to the front, put 都 after it, and the universal reading snaps into place. Without the fronting, the construction fails. 他吃什么都 is ungrammatical; 他什么都吃 is perfectly natural.

The 都不 / 不都 distinction is the single most common 都 error in intermediate Mandarin. The confusion is understandable: both sentences have the same words, and English doesn't reliably signal this difference in word order. "They don't all come" and "None of them come" are two very different claims, but learners writing fast under pressure tend to lose track of which they intend.

A useful test: can you follow the sentence with "but some do"? If yes, use 不都 (partial negation). If the sentence means every single member is excluded, use 都不 (total negation). 他们都不来，一个也没有 ("None of them are coming, not a single one") is total. 他们不都来，有几个不来 ("Not all of them are coming — a few aren't") is partial.

When 都 precedes a time expression, it shifts from universal quantification to scalar emphasis: "as much as X" or "already X," with an implied sense that X is surprising or further along than expected. This is 都 scoping over a time or degree expression that has been fronted — the same leftward rule, now applied to a point on a scale rather than a set of entities.

都两点了 means "it's already two o'clock" and carries the subtext: we've arrived at this late/surprising point. The 了 that typically closes these sentences reinforces the sense of a threshold reached. 都这么晚了还不睡 is something a parent says to a child who should have been in bed an hour ago: "It's already this late and you're still not sleeping." Both 都 and 了 are doing work here — 都 frames the degree as unexpectedly high, 了 marks it as the present relevant situation.

都 and 也 are both pre-verbal adverbs and they both come up in sentences about multiple people or things, which makes them feel interchangeable. They are not. 都 says something is true of every member of a group simultaneously. 也 says a new member is being added to a set for which the predicate is already established.

我们都喜欢音乐 = "we all like music" (one statement applying to the entire group). 我也喜欢音乐 = "I also like music" (you've already established that others like music; I'm adding myself to that set). The quick test: can you substitute "every X" for the subject? If yes, use 都. Is the sentence adding one more item to an already-established set? Use 也.

The sentences 我们都来了 (we all came) and 我们也来了 (we also came) are both grammatical but mean entirely different things. The first says every one of us showed up. The second says our group came too, in addition to whoever else was already there.

In spoken Mandarin, 都 stretches beyond pure quantification into an emphatic register where it functions closer to "even." This use typically appears in sentences with 连 lián (even, including) or in short exclamatory frames without it. 连我都不会这道题 — "even I can't do this problem" — is the full 连...都 construction, one of the most reliable patterns in the language for marking scalar extremity: if even this extreme case is included, then all lesser cases certainly are.

The short form without 连 appears in highly colloquial speech: 这点事都做不了？ "You can't even handle this small thing?" The 都 here signals a low threshold on a scale — if you can't manage even this, things are bad. 都怪你 ("it's entirely your fault") uses 都 for total attribution of blame: no other cause is acknowledged.