If it possible, can you explain the differences between yet and already?
The general rule:
already - in positive sentences
yet - in negatives and questions
I've been to the bank already.
Have you been to the bank yet?
I haven't been to the bank yet.
If you have reasons to believe that the action has been performed, you can use already in a question.
Have you been to the bank already? (You see a heap of banknotes on the table)