美国英语听力80篇2 Lesson38

[00:05.49]Why are some people left-handed?
[00:09.09]Scientists have been trying to answer that question for many years.
[00:14.32]Research has shown that ninety percent of people naturally use their right hands for most tasks.
[00:22.94]But hundreds of millions of people use their left hands.
[00:28.45]A study done in 1992 found that men are more likely to be left-handed than women.
[00:37.83]It also found that Asian or Hispanic people are less likely to be left-handed than white people,
[00:47.41]black people or North American Indians.
[00:51.33]Some cultures accept people who do things mostly with their left hands.
[00:58.10]Others do not.
[01:00.29]For example, in some countries eating with the left hand is considered an insult¹ to others.
[01:08.81]In the past, some parents and teachers forced lefthanded children to use their right hands instead.
[01:17.69]Scientists want to know the reason for left-handedness
[01:23.67]because it is closely² linked to mental problems like schizophrenia and language difficulties.
[01:30.91]One idea about the cause of left-handedness is the genetic⁴ theory.
[01:36.91]It says that people are right- or left-handed because of genes⁵ passed to them by their parents.
[01:44.62]For example, it has been shown that the handedness of adopted children
[01:49.87]is more likely to follow that of their birth parents than their adopted parents.
[01:55.93]Other evidence of genetic involvement can be found in some families.
[02:01.57]One famous example is the left-handed members of the present British Royal Family.
[02:08.84]These include the Queen Mother, her daughter Queen Elizabeth the Second,
[02:14.06]the Queen's son Prince Charles and his son Prince William.
[02:19.55]Amar Klar at the National Cancer Institute in Washington D.C. believes right-handed people are born with a gene³ for it.
[02:31.59]But, he says, about twenty percent of people do not have the right-handed gene.
[02:38.25]These people could be either left- or right-handed.
[02:43.13]Doctor Klar wants to find this gene.
[02:47.05]He plans to test the genes of members of 100 families
[02:53.17]in which at least one parent is right-handed and two of the children are left-handed.
[03:00.72]He will look for markers in the DNA⁶ to see how often the children have the same markers as the parents.
[03:10.41]Stanley Coren of the University of British Columbia in Canada thinks the reason for left-handedness is linked to fetal development.
[03:21.35]This idea says left-handedness results from damage to a fetus⁷ during or before birth.
[03:29.45]One cause of such damage could be an unusual position of the fetus in the mother's uterus.
[03:37.21]Another cause could be unusual levels of chemicals in the uterus.
[03:41.99]Doctor Coren says this damage could explain why a larger percentage of left-handed people have mental and health problems.
[03:52.86]Both these ideas have been offered to explain a situation that has been,a mystery to scientists for a long time:
[04:04.04]how can two babies who developed from the same egg and have the same genes use different hands?
[04:13.23]In 18% of identical⁸ twins,one twin is right-handec and the other is left-handed.
[04:21.93]One possible answer is that both twins lack the right-handed gene,
[04:28.33]so each has a chance to be either right-or left-handed.
[04:33.32]Another possible answer is that the difference is the result of damage caused by both babies being in a crowded uterus.
[04:43.90]Still other scientists say handedness could have more than one cause which could include both genetics and development.
[04:55.26]Experts also link left-handedness to artistic⁹ and athletic¹⁰ ability as well as extremely high intelligence.
[05:05.71]They say a great number of left-handed people were famous political leaders, artists, scientists or athletes.
[05:15.74]These include the political leaders Alexander the Great and Napoleon Bonaparte. The musicians Sergei Rachmanineff and Ludwig Van Beethoven.
[05:26.30]The artists Michelangelo,Leonardo da Vinci and Pablo Picasso.
[05:31.49]The scientist Albert Einstein.
[05:33.87]And the baseball player Babe Ruth.
[05:36.95]Other experts say every American president in the last twenty-five years has been at least partly left-handed,except for Jimmy Carter.
[05:48.50]They are Gerald Ford¹¹, Ronald Reagan,George Bush and Bill Clinton.
[05:54.87]However, some left-handed people were famous criminals.
[05:59.68]They include Billy the Kid, Jack¹² the Ripper and the Boston Strangler.
[06:06.32]Much interesting information about left-handedness can be found on the Internet computer network.

1 insult   

vt.侮辱，凌辱；n.侮辱的言词或行为

参考例句：

• You will insult her if you don't go to her party. 你要是不去参加她举办的聚会，就对她太无礼了。
• I can't sit down with that insult.我不能忍受那种侮辱。

2 closely   

adv.紧密地；严密地，密切地

参考例句：

• We shall follow closely the development of the situation.我们将密切注意形势的发展。
• The two companies are closely tied up with each other.这两家公司之间有密切联系。

3 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

6 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

7 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

8 identical   

adj.完全一样的，完全相同的；同一的

参考例句：

• She wore the identical dress on both occasions.她在两种场合穿的是同一件衣服。
• He is identical in character with his wife.他的品性和他的夫人相同。

9 artistic   

adj.艺术(家)的，美术(家)的；善于艺术创作的

参考例句：

• The picture on this screen is a good artistic work.这屏风上的画是件很好的艺术品。
• These artistic handicrafts are very popular with foreign friends.外国朋友很喜欢这些美术工艺品。

10 athletic   

adj.擅长运动的，强健的；活跃的，体格健壮的

参考例句：

• This area has been marked off for athletic practice.这块地方被划出来供体育训练之用。
• He is an athletic star.他是一个运动明星。

11 Ford   

n.浅滩，水浅可涉处；v.涉水，涉过

参考例句：

• They were guarding the bridge,so we forded the river.他们驻守在那座桥上，所以我们只能涉水过河。
• If you decide to ford a stream,be extremely careful.如果已决定要涉过小溪，必须极度小心。

12 jack   

n.插座，千斤顶，男人；v.抬起，提醒，扛举；n.（Jake）杰克

参考例句：

• I am looking for the headphone jack.我正在找寻头戴式耳机插孔。
• He lifted the car with a jack to change the flat tyre.他用千斤顶把车顶起来换下瘪轮胎。