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
2023-06-25
13
管理
问题
You can tell the age of a tree by counting its rings. But these records of tree’ s life really say a lot more. Scientists are using tree rings to learn what’s been happening on the sun’s surface for the last ten thousand years. Each ring represents a year of growth. As a tree grows, it adds a layer to its trunk taking up chemical elements from the air. By looking up the elements in the rings from the given year, scientists can tell what elements were in the air that year. Dr. Stevenson is analyzing one element—carbon-14 in rings 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 is 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 16 to 18 are based on the passage you have just heard.
16. What is the purpose of the scientists in studying tree rings?
17. What affects the amount of carbon-14 on earth?
18. What do we learn from the passage about the solar wind activity?
选项
A、To examine the chemical elements in the Ice Age.
B、To learn what’ s been happening on the sun’ s surface
C、To analyze the composition of different trees.
D、To find out the origin of carbon-14 on Earth.
答案
B
解析
细节辨认题。短文第二句指出Scientists are using tree rings to learn what’s been happening on the sun’s surface for the last ten thousand years,故科学家研究树年轮的目的是为了调查在过去一万年前太阳表面到底发生了什么。所以选项B正确。
转载请注明原文地址:https://www.tihaiku.com/zcyy/2780693.html
相关试题推荐
[originaltext]W:Pleasehaveaseat,Mr.Saunders.Ireceivedyourresumelast
[originaltext]ADanishpoliticianwhotriedtopostaphotoofCopenhagen’s
[originaltext]ADanishpoliticianwhotriedtopostaphotoofCopenhagen’s
[originaltext]AlmostallstatesinAmericahaveastatefair.Theylastfor
[originaltext]AlmostallstatesinAmericahaveastatefair.Theylastfor
[originaltext]Duringa1995roofcollapse,afirefighternamedDonaldHerbe
[originaltext]MymotherwasborninasmalltowninnorthernItaly.Shewas
[originaltext]MymotherwasborninasmalltowninnorthernItaly.Shewas
[originaltext]Obtaininggoodhealthinsuranceisarealnecessitywhileyou
[originaltext]Obtaininggoodhealthinsuranceisarealnecessitywhileyou
随机试题
FromhumblebeginningsinagarageinMenloPark,Californiain1998,Google
Somepeoplethinkthatwiththedevelopmentoftechnology,ourtraditionalc
F公司成功中标S市的电子政务工程。F公司的项目经理李工组织相关人员对该项目的工作
资产负债表的作用不包括()。A、资产负债表可以为收益把关 B、资产负债表上的
属于钢筋混凝土结构构造裂缝产生原因的有()。A.水泥安定性不合格 B.骨料为
高压电力电缆不需停电的工作,应填用()工作票。 A.第一种B.第
A. B. C. D.
小王在走访社区低保户老张一家时发现,老张几年前下岗,妻子因病卧床多年,儿子正在读
复方己酸羟孕酮注射液注射后,若出现经期延长,己出血较多日期时,可A.增加剂量,重
(2016年真题)下列水泵类型中,不属于叶片泵的是( )。 A.离心泵 B
最新回复
(
0
)