Many of us remember being in awe(敬畏) when we saw cloned dinosaurs running wild in the film Jurassic Park. And the idea of using technology to revive(恢復(fù)) extinct species has long fascinated not only writers and directors, but scientists as well.
According to The Telegraph, woolly mammoths(長(zhǎng)毛猛犸象), which featured in the popular Ice Age animated movie series, “may walk the earth once more” now that scientists have taken another step toward realizing a long-held dream—recreating their DNA.
Mammoths became extinct around 10,000 years ago. However, since the discovery of near-perfect preserved remains in Arctic permafrost(北極凍土帶) in May 2013, a variety of research studies have been carried out since.
Geneticists from Harvard University analyzed DNA from the remains, looking for genes which separated mammoths from elephants, such as hairiness and ear size. They then used the results to reproduce exact copies of 14 mammoth genes. “It is the first time that mammoth genes have been alive—although so far it has only been done in the lab,” George Church, lead researcher of the project, told the Sunday Times.
Church then used a new technique which allows scientists to edit DNA carefully, replacing sections of elephant DNA with the mammoth genes. So “we now have functioning elephant cells with mammoth DNA in them,” he said.
However, Church ruled out the possibility of bringing the mammoths back to life via cloning from frozen remains. He said he “preferred to focus on rebuilding the full mammoth genome(基因組) by analyzing DNA from preserved remains and putting it into the cells of its closest living relative – the Asian elephant,” reported The Telegraph.
Church argued that the return of the woolly mammoth—or rather, the return of something very similar—could help bring back fragile(脆弱的) ecosystems. However, some scientists believe that bringing back the mammoth would be unethical.
Professor Alex Greenwood, an expert on ancient DNA, said: “We may face the extinction of African and Asian elephants. Why bring back another elephant from extinction when we cannot even keep the ones that are not extinct around?” he told the Sunday Times. “What is the message? We can be as irresponsible with the environment as we want. Then we’ll just clone things back?”
“Money would be better spent focusing on conserving what we do have than spending it on an animal that has been extinct for thousands of years,” he said.
1.We can learn from the article that ______.
A. cloned mammoths followed cloned dinosaurs to get revived
B. the technology to revive mammoth genes is already mature
C. George Church and his colleagues tried to reproduce mammoth DNA
D. Church and his team managed to list all the genes that separate mammoths from elephants
2.According to Church, what is the significance of his study?
A. It could help prevent the extinction of the Asian elephant.
B. It could help people better tell elephant DNA from mammoth genes.
C. It could help bring back some extinct species and save fragile ecosystems.
D. It could help bring mammoths back to life via cloning from frozen remains.
3.The underlined word “unethical” in Paragraph 7 is closest in meaning to ______.
A. unacceptable B. misled
C. impractical D. illegal
4.According to the article, Professor Alex Greenwood believes that _______.
A. there is no need to worry about the extinction of African and Asian elephants at present
B. it’s necessary to bring back species that are beneficial to human beings from extinction
C. the return of the woolly mammoth would help to balance ecosystems
D. it’s more important to protect present species than to bring back extinct ones
年級(jí) | 高中課程 | 年級(jí) | 初中課程 |
高一 | 高一免費(fèi)課程推薦! | 初一 | 初一免費(fèi)課程推薦! |
高二 | 高二免費(fèi)課程推薦! | 初二 | 初二免費(fèi)課程推薦! |
高三 | 高三免費(fèi)課程推薦! | 初三 | 初三免費(fèi)課程推薦! |
科目:高中英語(yǔ) 來(lái)源:山東省濟(jì)寧市2017屆高三第二次模擬考試英語(yǔ)試卷 題型:書(shū)面表達(dá)
假如你是李華, 你校交流生Peter暑假期間想找一份兼職。你碰巧在網(wǎng)上讀到了下面的一則廣告,感到很適合他。請(qǐng)根據(jù)以下信息和要點(diǎn),用英語(yǔ)給他寫(xiě)封郵件向他推薦這份工作。
SUMMER HOLIDAYS TOUR GUIDES WANTED
Duties:
●To conduct tours for foreign visitors;
●To assist with travel and transportation arrangements.
Qualifications:
●Fluency in Chinese & English;
●Outgoing personality
If interested, please e-mail at Qufutravelservices@.com
1.寫(xiě)信目的;
2.工作內(nèi)容和招聘要求;
3.詢問(wèn)是否感興趣。
注意:
1.詞數(shù)100左右;
2.可適當(dāng)增加細(xì)節(jié),以使行文連貫;
3.不能使用真實(shí)姓名和學(xué)校名稱。
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
___________________________________________________________________________
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:內(nèi)蒙古2017屆高三上學(xué)期第一次月考英語(yǔ)試卷 題型:七選五
Secret codes(密碼)keep messages private. Banks, companies, and government agencies use secret codes in doing business, especially when information is sent by computer.People have used secret codes for thousands of years.1.Code breaking never lags(落后)far behind code making. The science of creating and reading coded messages is called cryptography.There are three main types of cryptography.2.For example, the first letters of “My elephant eats too many eels” spell out the hidden message “Meet me.” 3.You might represent each letter with a number, for example. Let’s number the letters of the alphabet, in order, from 1 to 26. If we substitute a number for each letter, the message “Meet me” would read “135520135.”A code uses symbols to replace words, phrases, or sentences. To read the message of a real code, you must have a code book.4.For example, “bridge” might stand for “meet” and “out” might stand for “me.” The message “Bridge out” would actually mean “Meet me.”5.However, it is also hard to keep a code book secret for long. So codes must be changed frequently.
A. It is very hard to break a code without the code book. |
B. In any language, some letters are used more than others. |
C. Only people who know the keyword can read the message. |
D. As long as there have been codes, people have tried to break them. |
E. You can hide a message by having the first letters of each word spell it out. |
F. With a code book, you might write down words that would stand for other words. |
G. Another way to hide a message is to use symbols to stand for specific letters of the alphabet. |
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:重慶市2016-2017學(xué)年高一下學(xué)期期中考試英語(yǔ)試卷 題型:短文填空
If you read a newspaper or listen to a newscast recently, you may hear or read a strange word, “staycation”. Staycation is 1. new word the American press is using 2. (describe) vacation very close to your own home, 3. simply staying at home during your vacation. It is a combination (合成) of the words “stay” and “vacation”.
According to many news reports, these staycations are very popular among American families this year. Why? The high price of gasoline for cars and airplanes has made it very costly for Americans to travel 4. (compare) to past years. When you combine this with the weak American dollar, it all adds up to people deciding to stay close to home 5. their traditional summer vacations. Without doubt, some places are more 6. (interest) to “stay at home” than others. And if you live in a very small town, well, you may just want to skip your vacation and save your time up to next year.
Everything is increasingly 7. (expense) nowadays, and let’s face it --- a vacation just may not be in your plan this year. You don’t have to give up family fun just because you can’t get away; instead, follow my tips for an 8. (economy) staycation filled with old favorites and new adventures! Staycations have 9.(achieve) high popularity in modern society in which 10. (employ) levels and gas prices are high.
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:江蘇省徐州市2016-2017學(xué)年高一下學(xué)期期中考試英語(yǔ)試卷 題型:翻譯
1.西方哲學(xué)之父蘇格拉底(Socrates)對(duì)西方的思想和科學(xué)有著深刻的影響。而亞歷山大大帝(Alexander the Great) 將希臘文化從歐洲傳到了非洲和亞洲,在此后的數(shù)個(gè)世紀(jì)中影響了整個(gè)世界。
2.很多人沒(méi)有充分認(rèn)識(shí)到吸煙對(duì)健康造成的傷害。這就是為什么我們選擇公益廣告--旨在就有關(guān)公共福利而教育人們.
3.他提議建一條雙軌隧道。人人都?xì)J佩他絕妙的幽默感。
4.他本該知道警察絕不會(huì)允許這類事情發(fā)生。但是Tazieff 經(jīng)常冒這樣的生命危險(xiǎn)。
5.飛機(jī)撒播了近一個(gè)月的種子。法國(guó)政府讓人把它包裝起來(lái),一部分一部分地搬回法國(guó)。
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:江蘇省徐州市2016-2017學(xué)年高一下學(xué)期期中考試英語(yǔ)試卷 題型:單項(xiàng)填空
A new trading agreement _______ between Holland and Denmark.
A. was drawn in B. was drawn up
C. has been made up D. had been drawn up
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:江蘇省徐州市2016-2017學(xué)年高一下學(xué)期期中考試英語(yǔ)試卷 題型:單項(xiàng)填空
With more forests _______, a huge quantity of good earth _______ every year.
A. being destroyed; is being washed away B. are being destroyed; is being washed away
C. being destroyed; are being washed away D. destroyed; are being washed away
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:甘肅省2016-2017學(xué)年高一下學(xué)期期中考試英語(yǔ)試卷 題型:閱讀理解
It seems that no one can live a happy life without friendship. While a great number of people expect others to be their friends, they don’t give friendship back. That is why some friendships don’t last long. To have a friend, you must learn to be one. You must learn to treat your friend the way you want your friend to treat you. Learning to be a good friend means learning three rules: be honest; be generous; be understanding.
Honesty is where a good friendship starts. Friends must be able to trust one another. If you do not tell the truth, people usually find out. If a friend finds out that you haven’t been honest, you may lose your friend’s trust. Good friends always depend on one another to speak and act honestly.
Generosity means sharing and sharing makes a friendship grow. You do not have to give your lunch money or your clothes. Naturally you will want to share your ideas and feelings. These can be very valuable to a friend. They tell your friend what is important to you. By sharing them, you help your friend know better.
Sooner or later everyone needs understanding and help with each other. Something may go wrong at school. Talking about the problem can make it easier to solve. Turning to a friend can be a first step in solving the problem. So to be a friend you must listen and understand. You must try to put yourself in your friend’s place so that you can understand the problem better.
No two friendships are exactly alike. But all true friendships have three things in common. If you plan to keep your friends, you must practice honesty, generosity and understanding.
1.Some friendships don’t last long because ________.
A. there are too many people who want to make friends
B. those who give others friendship receive friendship from others
C. some people receive friendship but don’t give friendship back
D. they don’t know friendship is something important
2.According to the passage, honesty is ________.
A. something impossible
B. more important than anything else
C. as important as money
D. the base of friendship
3.Which of the following isn’t talked about in the passage?
A. You should tell your friends the truth.
B. A friend who gives you his lunch money is a true friend.
C. Discussing your problems with your friends often helps to solve the problem.
D. Sharing your mind with your friends is valuable.
4.The best title of this passage is ________.
A. Honesty Is the Best Policy
B. A Friend in Need Is a Friend indeed
C. Three Important Points in Life
D. How to Be Friends
查看答案和解析>>
科目:高中英語(yǔ) 來(lái)源:山東省濟(jì)寧市2016-2017學(xué)年高一下學(xué)期第三學(xué)段考試英語(yǔ)試卷 題型:書(shū)面表達(dá)
假如你是李華,最近收到英國(guó)筆友Tom的來(lái)信。他想了解你校如何維護(hù)學(xué)生在校期間的安全。請(qǐng)你給他寫(xiě)一封英語(yǔ)回信,介紹你校的做法,如重視安全問(wèn)題、加強(qiáng)安全教育、增加保安人員、來(lái)訪登記等。
注意:1.信的內(nèi)容可適當(dāng)發(fā)揮;
2.詞數(shù)120左右(信的開(kāi)頭和結(jié)尾已給出,但不計(jì)入總數(shù))。
3.參考詞匯:安全意識(shí)awareness of safety;登記register;保安security guard
Dear Tom,
I’m glad to receive your letter and thank you for your concern about our students’ security.
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
___________________________________________________________
We believe a safer school will provide a better learning environment for us students.
Yours,
Li Hua
查看答案和解析>>
百度致信 - 練習(xí)冊(cè)列表 - 試題列表
湖北省互聯(lián)網(wǎng)違法和不良信息舉報(bào)平臺(tái) | 網(wǎng)上有害信息舉報(bào)專區(qū) | 電信詐騙舉報(bào)專區(qū) | 涉歷史虛無(wú)主義有害信息舉報(bào)專區(qū) | 涉企侵權(quán)舉報(bào)專區(qū)
違法和不良信息舉報(bào)電話:027-86699610 舉報(bào)郵箱:58377363@163.com