There are several explanations for why the circle is divided into 360 parts. Probably the

best explanation is connected with the Babylonians(巴比伦人).

Many, many centuries ago, large distances were measured in the Babylonian mile. The Babylonian mile equaled about seven of our miles. Because of its length, the time needed to travel the Babylonian mile became a measure of time. One day was said to be twelve Baby-Ionian time-miles.

About one thousand years before Christ, the Babylonians began keeping records of star movements. They needed a way to record how much time passed between the moment they first saw a star and then observed it again. They used the Babylonian time-mile as their measure of time.

In order to have small units of time, the Babylonians divided their time-mile into thirty parts. The Babylonians believed that each trip around the sky was a circle. One complete trip around the sky, they reasoned, took one day.

You already know that one day was the same as twelve Babylonian time-mile. Since each time-mile was divided into thirty parts, the circular trip around the sky was 12×30, or 360 parts long. That is how there came to be 360 4egrees in a circle.

The purpose of this passage is to explain ______.

A．how the Babylonians measured the time of star movements

B．why the circle is divided into 360 degrees

C．the Babylonian mile and the Babylonian time-mile

D．the Babylonians' ideas about the sky