1.Have you ever seen a yak?
2. Marl saw Jennifer three days ago.
3.They have already checked in for the flight.
4. How long ago did the bus leave?
5.Have you writen your diary yet?
6.I have just heard about the fire.
7. Theit plane lent at 6.45 this morning.
8. We have not spoken Englich since we arrived.