Learn Hardcore Chinese: tā yǐjīng huíqù le.

It marks a completed action and signals a new situation: she has gone back and is no longer here. In this sentence, 了 is closely tied to the verb phrase (回去) and presents the action as accomplished.

Is 了 just a past tense marker?

No. Chinese doesn’t mark tense the way English does. 了 marks aspect (completion/change), not “past.” With a future time word you can still see 了, e.g. 她明天就回去了, meaning “by tomorrow, the going-back will be completed.” With 已经 here, the time reference is effectively “by now.”

Can I omit 了 and just say 她已经回去?

In this simple sentence, don’t omit it—她已经回去 feels incomplete or unnatural in most contexts. Keep 了 with 已经 to show the action is already done: 她已经回去了. When you negate with 没(有), you drop 了: 她还没(有)回去.

How do I negate this sentence?

Use 没(有) for completed/realized actions:

她还没回去。 / 她还没有回去。 = She hasn’t gone back yet. Don’t use 不 for past/completed events here; 她不回去 means “she isn’t going back (she refuses/won’t),” not “hasn’t gone back.”

What’s the difference between 回去 and 回来?

Direction relative to the speaker:

回去: go back away from where the speaker is (return to there).
回来: come back to where the speaker is (return to here). So 她已经回去了 implies she went back to some other place, not to where the speaker currently is.

Why use 回去 instead of just 去?

回 means “to return,” so 回去 is “to go back.” 去 alone just means “to go,” with no “return” idea. If you say 她已经去了, without a destination it sounds like “she already went (somewhere),” not necessarily “went back.” If you mean “she left,” a common phrasing is 她已经走了.

Where does 已经 go in the sentence?

Typically: Subject + 已经 + Verb Phrase (+ 了).

她已经回去了。 You can add a time word before or after the subject:
今天她已经回去了。 / 她今天已经回去了。 Placing 已经 at the very end (…已经) is not idiomatic.

Can I use 过 instead of 了, e.g., 她已经回去过?

You can say 她回去过 (she has gone back before), but it means “past experience at some point,” not “she has just/already gone back now.” 已经 + 过 is fine when you mean “already had the experience,” e.g., 她已经回去过两次. Don’t stack 过 and 了 on the same verb to mark completion; they express different aspects.

How do I ask this as a yes–no question?

Common options:

Add 吗: 她已经回去了吗？
A-not-A pattern with 没: 她回没回去？ or 她去没去（呢）？ Both are natural.

What does the sentence imply about her current location?

It implies she is no longer here; the new situation is that she’s back at that other place (home, office, etc.) relevant to the context.

How do I pronounce it (tones and neutral tone)?

她 tā (1st)
已经 yǐjīng (3rd, 1st)
回去 huíqù (2nd, 4th)
了 le (neutral tone) Note: 她/他/它 are all pronounced tā (1st); only the characters indicate female/male/“it.”

Can I drop the subject and just say 已经回去了?

Yes, if the context makes the subject clear (e.g., in reply to 她在吗？). Chinese often omits known subjects.

What if I want to specify the place, like “home” or “school”?

Use a place noun with 回:

她已经回家了。 (home)
她已经回学校了。 or 她已经回学校去了。 The version with …回学校去了 highlights motion away from the speaker. All are natural.

Is there a softer or hedged version?

Soften/inform: 她已经回去啦。 (啦 is colloquial)
Hedge/guess: 她已经回去了吧。 (吧 indicates conjecture)

Does 已经 have to be there? What changes if I say 她回去了?

她回去了 still usually conveys “she’s gone back (already)” from context. 已经 adds explicit emphasis to the “already” part. Use it when you want to highlight that the action is earlier than expected or contrasts with someone’s assumption.

How do I say “She had already gone back (by then)”?

Chinese shows that with context/time words, not verb tense:

那时她已经回去了。
她当时已经回去了。
Or emphasize early completion: 她早就回去了。