Already, Still, Yet

Already = something that has happened in advance, or happened sooner than expected.
Example:
She's already made reservations for the restaurant.
He's already arrived at the meeting.

Still = something that is continuing and hasn't stopped or changed.
Example:
She's still writing that report for the boss.
He still works for the same company.

Yet = until now.
Example:
They haven't made their decision yet.
His plane hasn't landed yet.

Notice that already and still come before the main verb, but yet usually comes at the end of a phrase / sentence.

The workers _____ know about the layoffs.
It's 21:00, and he's _____ at the office.
She _____ ate, so she's just having coffee.
The class isn't finished _____.
He _____ has many friends at the local.
Mark isn't here _____. Can you give him a call?
We've _____ seen this movie, so we don't want to see it again.
He hadn't read the book _____, so he wasn't sure what she was talking about.
The test results _____ aren't satisfactory.
She can _____ remember using carbon paper to make copies of letters.
We'd better leave for the airport--it's _____ 11:00!
Don't say anything to the boss _____!