An area code is a section of a telephone number which generally represents the geographical area that the phone receiving the call is based in. It is the two or three digits just before the local number. If the number 16 is in the same area as the number making the call, an area code usually doesn’t need to be dialed. The local number, 17 , must always be dialed in its entirety.
The area code was introduced in the United States in 1947. It was created 18 the format of XYX, with X being any number between 2-9 and Y being either 1 or 0. Cities and areas with higher populations would have a smaller first and third digit, and 1 as the center digit. New York, being the largest city in the United States, was 19 the 212 area code, followed by Los Angeles at 213.
In countries other than the United States and Canada, the area code generally determines
the 20 of a call. Calls within an area code and often a small group of neighboring area codes are normally charged at a lower rate than outside the area code. 【題組】19. (A) reserved (B) assigned (C) represented (D) assembled