阅读理解
There are several explanations for why the circle is divided into 360 parts. Probably the best
explanation is connected with the Babylonians.
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 Babylonian 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 x 30,or 360 parts long. That is how
there came to be 360 degrees in a circle.


1. The purpose of this passage is to explain         .

A. how the Babylonians measured the time of  star movements
B. why the circle is divided int0 360 degrees
C. the Babylonian mile and the Babylonian time-mile
D. the Babylonians' ideas about the sky

2. For what was the Babylonian time-mile divided into thirty parts?

A. To make a day into 360 parts.
B. To make a circle into 360 parts.
C. To measure more exact distances.
D. To measure more exact time.

3. We conclude the one Babylonian time-mile equals          .

A. two hours
B. about seven miles
C. one day
D. twelve degrees

4. Suppose o on the following circle was the time the Babylonians first saw a star,and then it took 13. 5
Babyloruan time-miles to see it again,where should the time be marked on the circle?

A. 45.
B. 90.
C. 135.
D. 315.

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