before now or before a particular time in the past
‘Lunch?’ ‘No thanks, I've already eaten.’
We got there early but Mike had already left.
used to express surprise that sth has happened so soon or so early
Is it 10 o'clock already?
You're not leaving already, are you?
used to emphasize that a situation or problem exists
I'm already late.
There are far too many people already. We can't take any more.
used to say that sth is annoying or boring and that you want it to stop
Already and yet are usually used with the present perfect tense, but in NAmE they can also be used with the simple past tense.
I already did it.
Did you eat yet?
However, this is much more common in spoken than in written English and some Americans do not consider it acceptable, even in speech. The present perfect is more common in NAmE and almost always used in BrE .
I’ve already done it.
Have you eaten yet?
Just is mostly used with the perfect tenses in BrE and with the simple past in NAmE .
( NAmE )