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 wh 题目和参考答案——青夏教育精英家教网—

题目内容

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 zebrafish to uniform gold by inserting a version of the pigment(色素) gene into a young fish．As with humans, zebrafish skin colour is determined by pigment cells, which contain melanosomes(黑色素)．The number, size and darkness of melanosomes per pigment cell determines skin colour．

It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation(变异) 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 zebrafish genes．

Humans acquired dark skin in Africa about 1．5 million years ago to protect bodies from ultra-violet rays(紫外线) 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 colour, 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 did on Michael Jackson．

1.What is the main idea of the passage?

A． People can’t change their skin colour without any pain．

B． The new discovery helped find ways to change skin colour safely．

C． Pop king Michael Jackson often changed his skin colour as he liked．

D． Scientists have found out that people’s skin colour is determined by the gene．

2.It can be inferred from the passage that ________．

A． nowadays changing the skin colour with the chemical treatment has bad effect

B． Europeans and Africans have the same genes

C． the new discovery could help to find medical treatments for skin cancer

D． there are two kinds of skin genes

3.Scientists have done an experiment on a dark-striped zebra fish in order to ________．

A． find the different genes of humans

B． prove the humans’ skin colour is determined by the pigment gene

C． find out the reason why the Africans’ skin colour is dark

D． find out the ways of changing people’s skin colour

4.Which of the following statements is TRUE?

A． Michael Jackson died of skin damage caused by chemical treatment．

B． American blacks produce more vitamin D with their skin than others．

C． The gene determining skin colour exists widely in whites, blacks and Asians．

D． The melanosomes in the skin of blacks usually cause skin cancer more often．

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相关题目

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。有两项为多余选项。

Muzak

The next time you go into a bank, a store, or a supermarket, stop and listen. What do you hear? 1. It’s similar to the music you listen to, but it’s not exactly the same. That’s because this music was especially designed to relax you, or to give you extra energy. Sometimes you don’t even realize the music is playing, but you react to the music anyway.

Quiet background music used to be called “elevator music” because we often heard it in elevators. But lately we hear it in more and more places, and it has a new name “Muzak”. About one-third of the people in America listen to “Muzak” every day. The music plays for 15 minutes at a time, with short pauses in between. It is always more lively between ten and eleven in the morning, and between three and four in the afternoon, when people are more tired. 2.

If you listen to Muzak carefully, you will probably recognize the names of many of the songs. Some musicians or songwriters don’t want their songs to be used as Muzak, but others are happy when their songs are chosen. Why? 3.

Music is often played in public places because it is designed to make people feel less lonely when they are in an airport or a hotel. It has been proven that Muzak does what it is designed to do. Tired office workers suddenly have more energy when they hear the pleasant sound of Muzak in the background. 4. Supermarket shoppers buy 38 percent more groceries.

5. They say it’s boring to hear the same songs all the time. But other people enjoy hearing Muzak in public places. They say it helps them relax and feel calm. One way or another, Muzak affects everyone. Some farmers even say their cows give more milk when they hear Muzak!

A. Some people don’t like Muzak.

B. The music gives them extra energy.

C. Music is playing in the background.

D. Factory workers produce 13 percent more.

E. Muzak tends to help people understand music better.

F. They get as much as $4 million a year if their songs are used.

G. Muzak is played in most of the big supermarkets in the world.

—Dad, I have been appointed as manager of our company, but I’m worried about it.

—Why worry? Increased responsibility can ______ your best qualities.

A. bring in B. bring about C. bring up D. bring out

课文填空

This gift was the Amber Room, 1. was given this name because several tons of amber were used to make it. The amber which was 2. had a beautiful yellow-brown colour like honey. The design of the room was in the fancy 3. popular in those days. It was also a treasure 4._ with gold and jewels, which took the country' s best artists about ten years to make.

However, the next King of Prussia, Frederick William I, to whom the amber room 5. , decided not to keep it. In 1716 he gave it to Peter the Great. In return, the Czar sent him a 6. of his best soldiers. So the Amber Room became part of the Czar' s winter palace in St Petersburg. About four metres long, the room served as a small 7. hall for important visitors.

However, some of the Nazis secretly 8. the room itself. In less than two days 100,000 pieces were put inside twenty-seven wooden boxes. There is no 9. that the boxes were then put on a train for Konigsberg, which was at that time a German city on the Baltic Sea. After that, what happened to the Amber Room 10. a mystery.

What a bargain！The price of this dress is_______ that of the skirt．

A．half not as much as

B．much not as half as

C．not half as much as

D．as much as not half

阅读下面短文，然后按要求写一篇150词左右的英语短文。

“When should I begin to acquire good habits?”a young boy asked his teacher.

“How old are you?” asked the teacher.

“Eight years old, sir.”answered the boy.

“Then you have just lost eight years,”the teacher replied.

There is no doubt that habits are formed at a very early age．When one is young, it is easy to acquire good habits.

Good habits are practices that help us in our daily life．The habit of brushing one’s teeth in the morning, for instance, keeps one’s teeth clean and prevents a bad smell which is unpleasant to others．Bad habits such as sticking one’s tongue out, biting one’s fingernails and picking one’s nose, are undesirable ways of behaving in front of others．If we want people to enjoy being with us, we should try to develop habits that are pleasant.

It is said, “We sow an act; we reap a habit．We sow a habit and we reap a character.” The habits we formed at an early age shape our character．Habits are like tributaries(支流) which flow into a river．The river is made up of all its tributaries; a person’s character is made up of all the habits that he or she has acquired over the years.

【写作内容】

1．以约30个词概括本文内容；

2．以约120个词谈谈你对好习惯养成的看法，并包括以下要点：

（1）你认为好习惯重要吗，为什么？

（2）你身上有哪些好习惯，它们对你的学习或生活有什么影响？

（3）怎样才能养成良好的习惯？

【写作要求】

1．作文中可以使用亲身经历或虚构的故事，也可以参照阅读材料的内容，但不得直接引用原文的句子。

2．作文中不得出现真实姓名和学校名称。

散步是一种良好的锻炼方式，它对我们的健康非常有益。请以“Walking to Keep Fit”为题写一篇100～120词的英语短文，介绍一下散步的好处以及你的建议。

注意：开头已给出，不计入总词数。

Walking to Keep Fit

As we all know，walking is a good way of exercise，which is beneficial to our health．_______________________________________________________________________

______________________________________________________________________________

短文改错

文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号(^)，并在其下面写出该加的词。

删除：把多余的词用斜线(＼)划掉。

修改：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1．每处错误及其修改均仅限一词。

2．只允许修改10处，多者（从第11处起）不计分。

Dear Mr. Brown,

I'm very thankful to you for invite me to stay with you in Beijing in the coming summer vacation. I have been dreamed of seeing you again so that I can get more help from you in my English learning. And I'm afraid I can't go to your place in this summer. I have promised my grandmother, she lives in the country, to spend the summer with her. She misses too much that I find difficult to refuse her invitation. I'm busy now prepare for my examination. I plan to visit you in winter if it convenient to you.

Best wishes,

Li Ming

完形填空

It was Christmas Eve 1881. I was 15 years old and feeling like the world was ________ for me because there hadn't been enough money to buy me the rifle that I’d wanted that year.

Pa came back in and there was ice in his beard. “Come on, Matt,” Pa said. “Dress warmly. It’s cold outside. We’re going to Widow Jensen’s. They are ________ wood.” Widow Jensen lived about two miles down the road. Her husband had died a year or so before and ________ her with three children, the oldest being eight.

I ________ went out with Pa and we ________ the sled high with wood. ________ we went to the store and Pa took down a big ham, some bacon, a sack of flour and some shoes, which were put into a smaller sack. We rode the two miles to Widow Jensen’s in ________ . I tried to think through what Pa was doing. I knew we didn’t have much money and Widow Jensen had ________ neighbors than us. It shouldn’t have been our ________ .

Widow Jensen opened the door and let us in. She had a blanket wrapped around her ________ . The children were wrapped in ________ and were sitting in front of the fireplace by a very small fire that ________ gave off any heat at all. “We brought you a few things , Ma’am，” Pa said and set down the sack of flour. I put the meat on the table. Then Pa handed her the sack that had the shoes in it.

She ________ and took the shoes out one pair at a time. I watched her carefully. She bit her lower lip to keep it from ________ and then tears filled her eyes and started running down her cheeks. She looked up at Pa like she wanted to say something, ________ it wouldn’t come out. “We brought a load of wood too, Ma’am,” Pa said. Then he turned to me and said，“Matt，go bring some in. ”

I wasn’t the ________ person when I went back out to bring in the wood. I choked and as much as I hate to ________ it, there were tears in my eyes too. In my mind I kept ________ those three kids huddled (蜷缩)around the fireplace and their mother standing there with tears running down her cheeks with so much ________ in her heart that she couldn’t speak. Just then the rifle seemed very ________ . Pa had given me the best Christmas of my life.

1.A. over B. complete C. lost D. boring

2.A. in between B. away from C. out of D. far behind

3.A. offered B. brought C. delighted D. left

4.A. excitedly B. hurriedly C. gratefully D. unwillingly

5.A. equipped B. placed C. loaded D. armed

6.A. Now B. Then C. Meanwhile D. Sometime

7.A. silence B. regret C. devotion D. condition

8.A. smarter B. tougher C. prettier D. closer

9. A. topic B. concern C. idea D. case

10.A. shoulders B. head C. arms D. feet

11.A. one B. the rest C. another D. the other

12.A. nearly B. hardly C. actually D. slowly

13.A. jumped B. laughed C. joked D. hesitated

14.A. trembling B. moving C. bending D. crying

15.A. and B. so C. or D. but

16.A. honest B. kind C. same D. disappointing

17.A. allow B. admit C. clarify D. confirm

18.A. seeing B. imagining C. cheering D. comforting

19.A. motivation B. gratefulness C. sympathy D. courage

20.A. typical B. valuable C. unimportant D. hopeless

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