Can people change their skin colour without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin colour. The gene comes in two versions, one of which is found in 99 per cent of Europeans. The other is found in 93 to 100 per cent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.
Scientists have changed the colour of a dark-striped zebra fish to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebra fish skin colour is determined by pigment cells, which contain melanosomes (黑色素體). The number, size and darkness of melanosomes per pigment cell determines skin colour.
It appears that, like the golden zebra fish, light-skinned Europeans also have a mutation (突變)in the gene for melanosome production. This results in less pigmented skin. However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebra fish genes.
Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun, which can cause skin cancer. But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng. Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin colours, said Cheng.
The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin colour without damaging it like chemical treatment done on Michael Jackson.
【小題1】According to the passage, scientists have found          .

A.people living in northern latitudes need more sunlight
B.the reason why people change their skin colour
C.the reason why people get skin cancer
D.the gene that determines skin colour
【小題2】We can infer from the passage that         .
A.people like to change their skin colour
B.a mutation in the gene for melanosome production is different in human and zebra fish gene
C.people will be able to change their skin colour without chemical treatment in the future
D.skin cancer can be cured now
【小題3】Which of the following is NOT mentioned according to the passage?
A.The version of the pigment gene of Asians and that of Africans are the same.
B.Scientists have succeeded in turning the colour of a dark-striped zebra fish into uniform gold.
C.Dark skin can protect bodies from utral-violet rays of the sun.
D.People like pop king Michael Jackson.
【小題4】The passage is probably taken from __________.
A.a novelB.a science report
C.a story bookD.a science fiction


【小題1】D
【小題2】C
【小題3】D
【小題4】B

解析試題分析:文章大意:本文主要講述基因決定人的膚色。但是科學家已經(jīng)發(fā)現(xiàn)可以用化學藥品改變膚色。
【小題1】主旨大意題:根據(jù)全文講述的主要內容得知:科學家們發(fā)現(xiàn)人的膚色是由基因決定的。選D。
【小題2】推理判斷題 從文章第二段的句子Scientists have changed the colour of a dark-striped zebra fish to uniform gold by inserting a version of the pigment (色素) gene into a young fish.:得知,人們可以用化學藥品改變膚色。選C。
【小題3】細節(jié)理解題:從第四段的句子:Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin colours, said Cheng. 可知A是對的,從第二段的句子:Scientists have changed the colour of a dark-striped zebra fish to uniform gold by inserting a version of the pigment (色素) gene into a young fish.可知B是對的,從第四段的句子:Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun, which can cause skin cancer.可知C是對的,但是文章沒有提到人們喜歡杰克遜。選D。
【小題4】推理判斷題,本文主要講述基因決定人的膚色。但是科學家已經(jīng)發(fā)現(xiàn)可以用化學藥品改變膚色。所以是一篇科普文章,應該選自科學報告。選B。
考點:考查科普類短文

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【小題2】The “byproduct” (Paragraph 1) most probably refers to     .
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【小題1】What does the underlined word “This” in Paragraph 3 refer to?

A.The development of intelligence 
B.The idea of multiple intelligences 
C.IQ isn’t everything for intelligence 
D.Alternative views have been put forward 
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A.Robert Plomin confirms genes have something in common 
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A.The relationship between genes and intelligence 
B.IQ benefits a lot from high intelligence 
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So Web conferencing is much cheaper and greener and more people are willing to host and attend a web conference.
【小題1】What is the passage mainly about?
A. Ways of protecting the environment.
B. B. Green benefits of Web conference.
C. Ways of hosting a Web conference.
D. Impacts of Web conferencing on costs.
【小題2】According to paragraph 1, many companies use Web conferencing because they ________.

A.are interested in using any new technology
B.believe that Web conferencing is more convenient
C.want to do something to protect the environment
D.haven’t enough money to hold a traditional conference
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A.will be e-mailed an invitation before the conference
B.are required to sit in the office together
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D.must have access to the Internet
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