是和

-Excuse me, could you tell me  where the  post office is ?
-Post office? ?It's not far from here. Do you know Xinhua Road?
-I am from the United States,  and this is my frist trip to your city. I know nothing about the city.
-Oh, welcome to our city! I 'll show you the road, please follow me.
-Thanks, by the way, where can I buy a map of the city?
-Just at the gate of the post office, look! The post office is just across the street.
-Thank you very much, goodbye.
-Goodbye.