首页
登录
职称英语
[originaltext] You can tell the age of a tree by counting its rings but thes
[originaltext] You can tell the age of a tree by counting its rings but thes
游客
2024-02-02
28
管理
问题
You can tell the age of a tree by counting its rings but these records of trees’ life really say a lot more. Scientists are using tree rings to learn what’s being happening on the sun’s surface for the last ten thousand years. F.ach ring represents a year of growth. As the tree grows, it adds a layer to its trunk taking up chemical elements from the air. By looking up the elements in the rings for a given year, scientists can tell what elements were in the air that year. Doctors Stevenson is analyzing one element — carbon-14 in ring from both living and dead trees. Some of the rings go back almost ten thousand years to the end of the Ice Age. When Stevenson followed the carbon-14 trail back in time, he found carbon-14 levels change with the intensity of solar burning. You see the sun has cycles. Sometimes it burns fiercely and other times it’s relatively calm. During the sun’s violent periods, it throws off charged particles in fast moving strings called solar winds. The particles interfere with the formation of carbon-14 on earth. When there’s more solar wind activity, less carbon-14 is produced. Ten thousand years of tree rings show that the carbon-14 level rises and falls about every 420 years. The scientists concluded that the solar wind activity must follow the same cycle.
Questions 20 to 22 are based on the passage you have just heard.
20. What do the scientists want to learn by using tree rings according to the passage?
21. What affects the amount of carbon-14 on earth?
22. What do we learn from the passage about the solar wind activity?
选项
A、To learn the chemical elements in the Ice Age for the last ten thousand years.
B、To learn the pattern of solar wind activity for the last ten thousand years.
C、To learn the composition of different trees for the last ten thousand years.
D、To learn what’s being happening on the sun’s surface for the last ten thousand years.
答案
D
解析
细节题。短文中提到,科学家们利用树的年轮来研究太阳表面发生的情况。
转载请注明原文地址:https://tihaiku.com/zcyy/3416684.html
相关试题推荐
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
随机试题
Americanstodaychooseamongmoreoptionsinmorepartsoflifethanhaseve
[audioFiles]2013w28/audio_ezfj_182_20138[/audioFiles]APerf
PASSAGETHREE[br]Whatisthenatureoftheactionofthepaint,accordingtot
Thesalesmanageraskshismeneveryweek(inform)______himofeverythingconc
Themostobviousdifferencebetweenrealessaysandthethingsonehastowr
治疗药物监测其临床意义()。A:指导临床合理用药、提高治疗水平 B:确定合并用
有助于确诊的检查为A、血培养 B、抗"O" C、EB病毒抗体 D、肝肾功能
下图右侧四个选项中,对左侧零件的四个立面呈现有错误的一项是: A.如上图所示
据统计,2007年1-8月份黑龙江省对俄贸易进出口实现69.8亿美元,增长72.
【病例摘要】 患者女性,20岁。 主诉:关节痛、皮疹1个月,水肿,尿少伴发热
最新回复
(
0
)