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
2023-07-08
76
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. Each 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、It affects the growth of trees.
B、It has been increasing since the Ice Age.
C、It is determined by the chemicals in the air.
D、It follows a certain cycle.
答案
D
解析
细节题。根据短文里科学家推论说太阳风活动也有同碳14一样的周期,可知选D。
转载请注明原文地址:https://tihaiku.com/zcyy/2817985.html
相关试题推荐
[originaltext]M:DoyoubelieveIwasupbefore8thismorning?W:(l)Before8?
[originaltext]M:DoyoubelieveIwasupbefore8thismorning?W:(l)Before8?
[originaltext]ArthurMiller(1915-2005)isuniversallyrecognizedasoneoft
[originaltext]ArthurMiller(1915-2005)isuniversallyrecognizedasoneoft
[originaltext]ArthurMiller(1915-2005)isuniversallyrecognizedasoneoft
[originaltext]Therewasagardenerwholookedafterhisgardenwithgreatc
[originaltext]Gettingridofdirt,intheopinionofmostpeople,isagood
[originaltext]W:Oh,hello,Iwouldlikesomeinformationontheschoolaquatic
[originaltext]W:Oh,hello,Iwouldlikesomeinformationontheschoolaquatic
[originaltext]W:Oh,hello,Iwouldlikesomeinformationontheschoolaquatic
随机试题
Howshouldoneinvestasumofmoneyinthesedaysofinflation(通货膨胀)?Left
Manyautomobileaccidentswere_____carelessdriving.A、attributedtoB、resulted
[originaltext]TheEuropeanCentralBankreleasedanewroundofmeasuresto
AlphaZeroseemstoexpressinsight.Itplayslikenocomputereverhas,intui
NowomancanbetoorichortoothinThissayingoftenattributedtothelat
双代号时标网络计划中采用波形线表示工作的()。A、逻辑关系 B、关键线路
市净率倍数法比较适用于资产流动性较高的企业,因此( )估值通常采用市净率法。
下列不是常用β内酰胺酶抑制剂的是A.甲氧西林B.他唑巴坦C.舒巴坦D.克拉维酸E
培训成果包含的类型有()A.认知成果 B.技能成果 C.情感成果 D.效
刺激性干咳或阵咳症状为主者宜用 (常见症状的自我药疗)A.黄连素 B.乳果糖
最新回复
(
0
)