used in negative sentences
You use yet in negative sentences to say that something has not happened up to the present time, although it probably will happen. In conversation and in less formal writing, you usually put yet at the end of a clause.
It isn't dark yet.
I haven't decided yet.
In formal writing, you can put yet immediately after not.
Computer technology has not yet reached its peak.
They have not yet set a date for the election.
‘have yet to’
Instead of saying that something ‘has not yet happened’, you can say that it has yet to happen. People often use this structure to show that they do not expect something to happen.
I have yet to meet a man I can trust.
Whether it will be a success has yet to be seen.
used in questions
You often use yet in questions when you are asking if something has happened. You put yet at the end of the clause.
Have you done that yet?
Have you had your lunch yet?
Many American speakers and some British speakers use the past simple in questions like these. They say, for example, ‘Did you have your lunch yet?’
Don't confuse yet with already. You use already at the end of a question to express surprise that something has happened sooner than expected.
Is he there already?
You mean you've been there already?
➜ See already
Don't use ‘yet’ to say that something is continuing to happen. Don't say, for example, ‘I am yet waiting for my luggage’. The word you use is still.
He still doesn't understand.
Brian's toe is still badly swollen.
➜ See still
If you don't intend to do something just yet, you don't intend to do it immediately.
It is too risky to announce an increase in our charges just yet.
I'm not ready to retire just yet.