改动如下：
Hi ,sara!
Thanks for your email.You can go out of the airport and turn left,then you'll see the bus stop.You can take a taxi there.The city center is about thirty kilometers long from the airport ,which may take about forty-five minutes there.You'll give the money to the driver when you arrived.And it may cost about twenty dollors.After you get off the taxi,you are at the AB avenue.Go along AB avenue to east and turn left at the second crossing into BC street.and go straight this road about fifty meters.You'll see my house on the right side of the road.Your plane will arrive at 11:00,so see you at about 12:00.
Best wishes,
Justin
you can take a taxi at there这句中把at去掉.