2009年职称英语综合类B级阅读判断真题答案

2009年职称英语综合类B级阅读判断真题答案,本站还有更多关于职称英语考试时间,职称英语考试成绩查询,职称英语考试试题,历年职称英语考试试题及答案解析的文章。
2009年度全国职称外语等级考试试卷 英      语 综合类B级   阅读判断(第16～22题，每题1分，共7分)       下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。   Radiocarbon Dating     Nowadays scientists can answer many questions about the past through a technique called radiocarbon(放射性碳)．or carbon-14，dating One key to understanding how and why something happened is to discover when it happened.     Radiocarbon dating was developedinthelatel940s by physicist Willard F Libby at the University of Chicago An atom of ordinary carbon called carbon-12 has six protons (质子)and six neutrons(中子)in its nucleus(原子核)Carbon-14，or C-14，is a radioactive unstable form of carbon that has two extra neutrons .It returns to e more stable form of carbon through a process called decay(衰减)This process involves the loss of the extra neutrons and energy from the nucleus.     In Libby’s radiocarbon dating technique，the weak radioactive emissions(放射)from this decay process are counted by instruments such as a radiation detector and counter．The decay rate is used to determine the proportion of C-14 atoms in the sample being dated.     Carbon-14 is produced in the Earth’s atmosphere when nitrogen(氨)-14．or N-14，interacts with cosmic rays(宇宙射线)Scientists believe since the Earth was formed，the amount of nitrogen in the atmosphere has remained constant Consequently,C-14 formation is thought to occur at a constant rate Now the ratio of C-14 to other carbon atoms in the atmosphere is known Most scientists agree that this ratio is useful for dating items back to at least 50．000 years.     All life on Earth is made of organic molecules(分子)that contain carbon atoms coming from the atmosphere So all living things have about the same ratio of C-14 atoms to other carbon atoms in their tissues(组织)Once an organism(有机体)dies it stops taking in carbon in any form，and the C-14 already present begins to decay Over time the amount of C-14 in the material decreases and the ratio of C-14 to other carbon atoms goes down In terms of radiocarbon dating．the fewer C-14 atoms in a sample，the older that sample is.
 
16 Nowadays many scientists depend on radiocarbon for dating age-old objects
A Right
B Wrong
C Not mentioned 17 The radiocarbon dating technique is only about 40 years old A Right
B Wrong
C Not mentioned
18 An atom of ordinary carbon has six protons and eight neutrons A Right
B Wrong
C Not mentioned 19 Radar is used to determine the characteristics of radiocarbon A Right
B Wrong
C Not mentioned 20 Radiocarbon is reliable in dating an object back to at least 50,000 years A Right
B Wrong
C Not mentioned
21 When an organism dies．the C-14 in it begins to decay． A Right
B Wrong
C Not mentioned
22 The half-life of C-14 is about 25,000 years A Right
B Wrong
C Not mentioned 【参考答案】 16. Nowadays many scientists depend on radiocarbon for dating age-old objects. (A： right, 该提问句内容可以由文章第一段第一句内容推断出来： Nowadays scientists can answer many questions abou the past through a technique called radiocarbon (放射性碳), or carbon-14, dating. (现在科学家们能通过一种被称为放射性碳， 即C-14的一种技术来测定年代， 回答许多关于过去的事情的问题))
17. The radiocarbon dating technique is only about 40 years old . (B: wrong,  文章中提到放射性碳测定技术是在20世纪40年代的末期被研制出来， 因此该提问句内容与文章中相关内容不一致， 该题考察细节信息的查找和确认)
18. An atom of ordinary carbon has six protons and eight neutrons. (B: wrong,  文章中说“普通的碳原子含有6个中子”，因此该提问句内容与文章中相关内容不一致， 该题考察细节信息的查找和确认)
19. Radar is used to determine the characteristics of radiocarbon. (C： Not mentioned, 该提问句内容在文章中没有被提及)
20. Radiocarbon is reliable in dating an object back to at least 50,000 years. (A: Right, 该提问句内容是对文章倒数第二段段落主题内容的概括)
21. The C-14 in an organism begins to decay when it falls. (A: Right, 该提问句内容是文章中相关语句“Once an organism dies it stops taking in carbon in any form, and the C-14 already presents begins to decay.(一旦生物体死亡， 它就会停止吸收任何形式的碳， 而生物体内的c-14也会开始衰减”的同义转述。)
22. The half-life of C-14 is about 25,000 years.. (B: Wrong,  该题属于常识题， C-14的半衰期是5568年左右， 不是25，000年。 )
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