早教吧作业答案频道 -->英语-->
阅读理解。RedDwarfRedDwarfstars(红矮星)canrangeinsizefromahundredtimessmallerthanthesuntoonlyacoupleoftimes
题目详情
阅读理解。 |
Red Dwarf Red Dwarf stars (红矮星) can range in size from a hundred times smaller than the sun to only a couple of times smaller. Because of their small size these stars burn their fuel very slowly which allows them to live a very long time. Some red dwarf stars will live trillions of years before they run out of fuel. Then why are red dwarf stars red? Beacuse red dwarf stars only burn a little bit of fuel at a time they are not very hot compared to other stars. Think of a fire. The coolest part of the fire at the top of the flame glows red the hotter part in the middle glows yellow and the hottest part near the fuel glows blue. Stars work the same way. Their temperatures determine what color they will be. Thus we can determine how hot a star is just by looking at its color. Like the Sun these medium(中等的) -sized stars are yellow because they have a medium temperature. Their higher temperature causes them to burn their fuel faster. This means they will not live as long only about 10 billion years or so. Near the end of their lives these medium-sized stars swell up becoming very large. When this happens to the Sun it will grow to engulf(吞 没) even the Earth. Finally they shrink again leaving behind most of their gas. This gas forms a beautiful cloud around the star called a Planetary Nebula(行星状星云) . When will the Sun expand into a giant and then shrink leaving behind a planetary nebula? Don't worry. The sun is only about 5 billion years old. It still has another 5 billion years before it will expand and then turn into a planetary nebula. The Sun is so hot that when it dies it will take a long time to cool off. The sun will die in about 5 billion years but it will still glow for many billions of years after that. As it cools it will be what is called a white dwarf star. Finally after billions maybe even trillions of years it will stop glowing at that point it will be what we call a black dwarf star. There are still no black dwarf stars in the Universe. |
1. Why do the Red Dwarf stars burn their fuel very slowly? |
A. Because they are small. B. Because they don't move around. C. Because they are cool. D. Because they reflect light like the moon. |
2. Which of the following best expresses the main idea of Paragra-ph 2? |
A. How red dwarf stars work. B. Why red dwarf stars burn a little fuel. C. Why red dwarf stars are red. D. How temperature determines the color. |
3. Which of the following is closest in meaning to the underlined phrase" swell up"in Paragraph 3? |
A. Become smaller. B. Become larger. C. Keep the same. D. Grow high. |
4. The title on the underline before Paragraph 3 is probably |
A. The Sun B. Yellow Stars C. Planetary Nebula D. Star Temperature |
5. Which of the following websites may this passage be taken from? |
A. www. plant. com B. www. oceans. com C. www. inventor. com D. www. kidsastronomy. com |
▼优质解答
答案和解析
1-5: ACBBD
看了阅读理解。RedDwarfRe...的网友还看了以下:
红红家书架有上、中、下三层,星期日红红帮爸爸整理书架,发现上层与中层放书本数的比是2:3,中层与下层 2020-03-30 …
红红家的书架有上、中、下三层,星期日红红帮爸爸整理书架,发现上层与中层放书本数的比是2:3,中层与 2020-04-27 …
阅读下文,完成文后各题.在火星上种庄稼火星是太阳系中八大行星之一,大量的铁氧化物覆盖在它的表面,让 2020-06-28 …
我有7个黄星,40个红星.串起来要使红星数量是黄星的5倍.问如红星不变,需减少或增加多少个黄星 2020-07-15 …
农村居民饮用水有法律保护吗?我的亲戚家住信宜市贺家管理区红星村,据了解他家的用水设备遭到人家的破坏, 2020-11-10 …
小小想做幸运星,要使红幸运星数量是黄幸运星的5倍.我有7颗黄幸运星,40颗红幸运星,如果黄幸运星数量 2020-11-20 …
1.小红获得老师奖励的小星星48枚,其中红色的占3/8,后来又奖励他几枚红色的小星星,这时红色的小星 2020-11-20 …
季末大酬宾,部分凉鞋打折处理。红星原价120元,促销期间打六五折。促销期间买一双红星凉鞋要多少钱﹖ 2020-11-21 …
我有7个黄星,40个红星.串起来要使红星数量是黄星的5倍.问如红星不变,需 2020-12-16 …
红星+星红+星红=爱星星问爱,红,星,各代表什么数字 2020-12-16 …