all large cities around the world have many post offices located throughout the city，and even the smallest village has at least one postal station. you may go to a post office to mail a letter.

　　however，there are mail boxes located on every second or third corner in all cities and towns.  any letter or small package having sufficient postage may be dropped in any of these mail boxes.

　　if a person wishes a letter to be delivered more quickly to the address，he may buy a special delivery stamp and delivery is made directly by the messenger instead of by the regular carrier.