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
2024-02-09
20
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、The lifecycle of trees.
B、The number of trees.
C、The intensity of solar burning.
D、The quality of air.
答案
C
解析
细节题。根据短文里提到太阳燃烧得越热烈,太阳风的活动就越频繁,碳14的数量就产生得越少。
转载请注明原文地址:https://tihaiku.com/zcyy/3434250.html
相关试题推荐
[originaltext]Americanofficialshavesuspendedallfishinginpartsofthe
[originaltext]Americanofficialshavesuspendedallfishinginpartsofthe
[originaltext]Americanofficialshavesuspendedallfishinginpartsofthe
[originaltext]Isittruethatyouwillfeelveryexcitedandhappywhenyou
[originaltext]M:So,canyouthinkofapersonthatyouadmiremost?W:Well,I
[originaltext]M:So,canyouthinkofapersonthatyouadmiremost?W:Well,I
[originaltext]M:So,canyouthinkofapersonthatyouadmiremost?W:Well,I
[originaltext]W:John,youlookterrific.Areyouworkingoutrecently?Yousur
[originaltext]W:John,youlookterrific.Areyouworkingoutrecently?Yousur
[originaltext]W:LookatthissuperbpaintingIboughttoday.Itonlycosts£1
随机试题
Completetheformbelow.WriteNOMORETHANTHREEWORDSAND/ORANUMBERforeach
[originaltext]M:Iseeyouareamotheroftwo.Doyouthinkyoucanmanageto
Manypeoplelikethegiganticwhales.Humansympathy【C1】______whalesis
网民Internetuser;netizen
但随着美国淡化反恐、强化战略重心东移,中美不仅既有的反恐合作出现松动,而且还面临
完全性心内膜垫缺损的彩色多普勒超声所见,下列错误的是A.收缩期可见蓝色血流束从左
A.同步二进制加法计数器 B.同步四进制加法计数器 C.同步三进制计数器
损失数据收集的核心环节主要包括()。A.损失事件识别 B.损失事件填报 C.
影响薪酬设定的外在因素包括()。A.劳动力市场的供需关系与竞争状况 B.地
腹部钝性损伤后,下列不是剖腹探查的适应证的是A.输血后休克又出现 B.腹腔穿刺
最新回复
(
0
)