https://online2.tingclass.net/lesson/shi0529/10000/10087/ly413.mp3
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America uses a freeway system. Freeways pass through all major cities and are used very frequently. If the distance is far, you probably will have to take the freeway. To give directions referring to the freeway, you use North, South, East, or West. Other ways you might hear are Northbound, Southbound, Westbound, or Eastbound.
Most freeways also have exit numbers. In many states, the numbers start at one from the beginning of the state border and increases by one every mile. If someone says you should take exit 178, you should stay on the road until you see exit 178. Each exit is clearly marked so you don't have to worry about missing it.
You will know you are going the wrong direction if the numbers are going in the wrong direction. For example, if you need to take exit 150, and the first exit number is 151, and the next one is 152, and the next one is 153, then you know you should turn around because the numbers are getting larger.