No, the mail hasn't arrived yet.
Yes, the mail has already arrived.
No, Adrian hasn't returned from lunch yet.
Yes, Adrian has already returned from lunch.
No, I haven't paid that bill yet.
Yes, I have already paid that bill.
No, George hasn't found his gloves yet.
Yes, George has already found his gloves.
No, the class hasn't begun yet.
Yes, the class has already begun.
No, the boat hasn't sailed yet.
Yes, the boat has already sailed.
