Sometimes in the month of November, a special event happens in the sky that observers may remember for a lifetime. (1) It is a meteor storm. Meteors are pieces of rock from space that burn up in our atmosphere. Meteor showers happen when the Earth passes through a large amount of space material during its orbit around the sun. However, thousands of meteors fall during a meteor storm. Some of them may briefly shine brighter than any star in the sky.

(2) In most years, it is not unusual. Leonid meteors fall at an average rate of only 15 each hour. However, every 33 years an object passes through our solar system that changes the Leonid meteor shower.

(3) Comets leave behind these materials as they orbit the sun. Each year around November 18, the Earth passes through material left behind by a comet called Tempel-Tuttle.

In February of 1998, the Tempel-Tuttle comet returned to the inner solar system. Astronomers have found that the Leonid meteor shower can become very active for about five years after the appearance of that comet.

Astronomers also have discovered that each appearance of the Tempel-Tuttle comet leaves behind a different path of material. (4) Some astronomers believe the Leonids this month may be a meteor storm.

This year, astronomers believe that there will be two periods of heavy meteor activity starting on November 18. At 10 Hours Universal Time, observers in North America should see a large number of meteors.

(5) Observers in East Asia and Western Australia will see it best. Astronomers who have researched the Leonids say the best chance to see a meteor storm may be this year and next year.

A.This discovery has permitted astronomers to know when the Leonid meteor shower may be most intense

B. Another period of meteor activity should happen at about 18 Hours Universal Time

C. Leonid meteors shower happens every year

D. The Leonid meteor shower happens every November

E. The event is more than a meteor shower

F. A comet is a large body of gas, ice and rock

正确答案:EDFAB

解析:前面讲到，十一月份在天空中有一个特殊的事件发生，本句话应该描述这个特殊事件是什么，因此选E。

本句是本段的主题句。后一句提到大多数年份中，这是经常发生的。后面的句中都在谈论Leonid流星，所以本句选D。

本句是本段的主题句。后面都在谈论彗星的情况，因此本句选F，解释什么是彗星。

前一句说有一些天文学家发现有关Tempel-Tuttle彗星的一些情况，所以本句应该接着谈这个发现，后一句谈本月Leonid的情况，因此选A。

上一段中提到流星活动有两个阶段，并且介绍了其中的一个阶段的内容，本句应该是介绍另一个阶段的内容。因此选B。

Energy of the Body

In some ways, the human body is both like a furnace and like an engine. It must have fuel to