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
2023-07-02
53
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/2800418.html
相关试题推荐
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
MillionsofAmericanslieawakeatnightcountingsheep,orhaveastiffdri
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[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
【B1】[br]【B7】[originaltext]NowwetraveltothenorthcentralpartoftheU
冲击系数kim的数值变化范围是()。A.0≤kim≤1 B.1≤kim≤2
商品的使用价值和价值的关系是:A.有使用价值的东西就有价值 B.有价值的东西不
下面关于WBS的描述,错误的是( )。A.WBS是管理项目范围的基础,详细描述
驾龄10年的司机在开车过程的注意属于:A.有意注意 B.无意注意 C.有意后
A.脾胃虚弱 B.燥热伤津 C.寒水上泛 D.湿热中阻 E.肝胃郁热口中
清代学者全祖望指出:“自明中叶以后,讲学之风,已为极弊,高谈性命,直人禅障,束书
肾虚型月经先后无定期的首选方是A.右归丸 B.固阴煎 C.定经汤 D.知柏
骨髓象显示,原始粒细胞Ⅰ型+Ⅱ型(原始单核细胞+幼稚单核细胞或者原始淋巴细胞+幼
2016年1~12月,国有企业营业总收入458978亿元,同比增长2.6%。其中
最新回复
(
0
)