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
2024-01-30
30
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://tihaiku.com/zcyy/3406590.html
相关试题推荐
[originaltext]ArmedcarjackerspickedthewrongmomtomesswithMondayeve
[originaltext]ArmedcarjackerspickedthewrongmomtomesswithMondayeve
[originaltext]Anextraordinarytreefrogthoughttohavediedoutmorethan
[originaltext]Somediseasesareinfectious—likecoldsandfluButwhatabou
[originaltext]Somediseasesareinfectious—likecoldsandfluButwhatabou
[originaltext]Climatechangeismakingitharderthanusualforscientists
[originaltext]M:Hi,Rose,youaresoabsorbedthatyoudidn’tevenknowIcame
[originaltext]M:Hi,Rose,youaresoabsorbedthatyoudidn’tevenknowIcame
[originaltext]M:Hi,Rose,youaresoabsorbedthatyoudidn’tevenknowIcame
[originaltext]W:Jack,Iheardyouwerelookingforajob.Haveyoufoundoney
随机试题
Withunemploymentrisingandhousingcostsstillhigh,citiesaroundthecou
100mphgalescausechaos【76】Strongwinds,whichat
Thepartoftheenvironmentalmovementthatdrawsmyfirm’sattentionisthe
《建筑灭火器配置验收及检査规范》(GB50444)适用于工业、民用,军工建筑中灭
复合会计分录是指()。A.一借一贷的会计分录 B.一借多贷的会计分录 C.多
女性,60岁,剑突下持续性疼痛6小时,寒战、高热伴黄疸,既往有类似发作史。查体:
当旧厂技术改造、生产规模显著扩大后,其经济效益则表现在产品成本的降低、产量的增长
( )须通过面向国内外的公开媒介和网络发布招标公告。A.国际邀请招标 B.国
下列货币形态中,属于代用货币的是()。A.贝壳 B.金币 C.交子 D.人
某项目现金流量如下表,则第3年初的净现金流量为( )万元。 A.-500
最新回复
(
0
)