B
During the Ice Age, the mammoths (猛犸象) lived both in Asia and America. But by about 4,000 years ago, the large and hairy elephants had disappeared.
Some scientists want to clone a mammoth, and the first need is some mammoth DNA. Since 1900s, scientists have been digging up remains (残骸) of mammoths in the cold ground. Some still even have their skin and hair. Unluckily, even when it's frozen, DNA still can't be kept very well. It starts to break apart soon after an animal dies. Scientists have found plenty of mammoth DNA—but it's all just short bits and in a mess.
Modern Asian elephants are cousins of the ancient mammoths. Their DNA is about 99% the same. Still, that adds up to 70 million differences. But if we could change the elephant's DNA in the places that are different, could we make mammoth DNA? Some researchers at Harvard are giving it a try. They have got out 14 bits of DNA in elephant blood cells that help mammoths stand the cold. It seemed to work. But they're only working with groups of cells, not a whole animal. There is still a long way to go before cloning a mammoth.
Even if scientists could clone a mammoth or other disappeared animals, would it be a good idea? It might be cool to see a real, living mammoth. But would such an animal be happy, with no other mammoths around? Who would teach it how to be a mammoth? There are important questions for trying to bring back any disappeared creature. Cloning is expensive and often fails. Would the money be better spent in saving endangered animals that are still alive?
(
A. It stayed the same. B. It got longer.
C. It disappeared. D. It broke apart.
(
A. The scientists are going to put the DNA of standing cold in another animal.
B. The scientists at Harvard have already cloned a mammoth very successfully.
C. It isn't easy to clone a disappeared animal though their DNA is close to some animals.
D. There are lots of differences of DNA between mammoths and modern Asian elephants.
(
A. In a story magazine. B. In a cartoon newspaper.
C. On a science website. D. In a fashion report.
During the Ice Age, the mammoths (猛犸象) lived both in Asia and America. But by about 4,000 years ago, the large and hairy elephants had disappeared.
Some scientists want to clone a mammoth, and the first need is some mammoth DNA. Since 1900s, scientists have been digging up remains (残骸) of mammoths in the cold ground. Some still even have their skin and hair. Unluckily, even when it's frozen, DNA still can't be kept very well. It starts to break apart soon after an animal dies. Scientists have found plenty of mammoth DNA—but it's all just short bits and in a mess.
Modern Asian elephants are cousins of the ancient mammoths. Their DNA is about 99% the same. Still, that adds up to 70 million differences. But if we could change the elephant's DNA in the places that are different, could we make mammoth DNA? Some researchers at Harvard are giving it a try. They have got out 14 bits of DNA in elephant blood cells that help mammoths stand the cold. It seemed to work. But they're only working with groups of cells, not a whole animal. There is still a long way to go before cloning a mammoth.
Even if scientists could clone a mammoth or other disappeared animals, would it be a good idea? It might be cool to see a real, living mammoth. But would such an animal be happy, with no other mammoths around? Who would teach it how to be a mammoth? There are important questions for trying to bring back any disappeared creature. Cloning is expensive and often fails. Would the money be better spent in saving endangered animals that are still alive?
(
D
) 5. What happened to mammoth DNA?A. It stayed the same. B. It got longer.
C. It disappeared. D. It broke apart.
(
C
) 6. What can we learn from the third paragraph?A. The scientists are going to put the DNA of standing cold in another animal.
B. The scientists at Harvard have already cloned a mammoth very successfully.
C. It isn't easy to clone a disappeared animal though their DNA is close to some animals.
D. There are lots of differences of DNA between mammoths and modern Asian elephants.
(
C
) 7. Where can we most probably read this passage?A. In a story magazine. B. In a cartoon newspaper.
C. On a science website. D. In a fashion report.
答案：【解析】：
这是一道英语阅读理解题，主要考查了学生对文章内容的理解和分析能力。题目给出了一个关于猛犸象和克隆技术的阅读材料，并附带了几个问题。学生需要通过阅读文章内容，理解文章的主旨和细节，然后根据文章内容选择正确的答案。
5. 题目问的是猛犸象的DNA发生了什么。根据文章第二段的内容，“It starts to break apart soon after an animal dies.”这句话直接说明了猛犸象死后，其DNA很快就开始分解，因此选项D“它分解了”是正确的。
6. 题目要求从第三段中学习到什么。第三段主要讲述了现代亚洲象与古代猛犸象的DNA相似度很高，但仍然存在很多差异，而且克隆猛犸象还有很长的路要走。选项C“尽管它们的DNA与某些动物相近，但克隆消失的动物并不容易”最符合文章主旨。
7. 题目问的是我们最可能在哪里读到这篇文章。由于文章主要讲述了猛犸象和克隆技术的相关知识，这是一篇科普文章，因此最有可能出现在科学网站上。选项C“在科学网站上”是正确的。
【答案】：
5. D
6. C
7. C
这是一道英语阅读理解题，主要考查了学生对文章内容的理解和分析能力。题目给出了一个关于猛犸象和克隆技术的阅读材料，并附带了几个问题。学生需要通过阅读文章内容，理解文章的主旨和细节，然后根据文章内容选择正确的答案。
5. 题目问的是猛犸象的DNA发生了什么。根据文章第二段的内容，“It starts to break apart soon after an animal dies.”这句话直接说明了猛犸象死后，其DNA很快就开始分解，因此选项D“它分解了”是正确的。
6. 题目要求从第三段中学习到什么。第三段主要讲述了现代亚洲象与古代猛犸象的DNA相似度很高，但仍然存在很多差异，而且克隆猛犸象还有很长的路要走。选项C“尽管它们的DNA与某些动物相近，但克隆消失的动物并不容易”最符合文章主旨。
7. 题目问的是我们最可能在哪里读到这篇文章。由于文章主要讲述了猛犸象和克隆技术的相关知识，这是一篇科普文章，因此最有可能出现在科学网站上。选项C“在科学网站上”是正确的。
【答案】：
5. D
6. C
7. C