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 of the sun(太阳光紫外线), 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.

51. The passage mainly tells us that ________.

  A. people can not change their skin colour without any pain

  B. the new discovery could lead to search into 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

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

  A. nowadays people who want to change their skin colour have to suffer a lot from the damage caused by the chemical  treatment

  B. Europeans and Africans have the same gene

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

  D. there are two kinds of genes

53. 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 peopl’s skin colour

54. The reason why Europeans are light-skinned is probably that ________.

  A. they are born light-skinned people

  B. light-skinned Europeans have mutation in the gen for melanosome production

  C. they have fewer activities outside

  D. they pay much attention to protecting their skin

55. The writer’s attitude towards the discovery is ________.

  A. neutral                      B. negative                   C. positive                    D. indifferent

Nowadays people sometimes separate their waste to make it easier for it ______．

       A．reusing           B．reused             C．reuses             D．to be reused

请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。

注意：每空格一个单词。

Some people believe that greed and selfishness has become the basis of modern society. We should return to the old traditions of family and community, and then we will have a better life. To what extent do you agree or disagree with the above opinion?

In this fast-paced world, many values are undergoing major changes. While people traditionally prioritize(区分优先次序) caring, sharing and generosity in life and work, modern people seem to be more self-absorbed and self-concerned.

Modern people act selfishly to survive the harsh competition of life. They say that it is a jungle out there. To survive, you have to fight with whatever means that come handy. Obviously greedy and selfishness go perfectly well with such ideas. In a company, employees do everything they can to get better pay and higher position, even at the cost of colleagues. We are in any way advocating any selfish conduct. It is just that people are pressured to act in a certain way due to outside influences.

In spite of common practice, it is hard to conclude that modern society is built on greed and selfishness, both of which are not newly invented vocabulary. In ancient times people also did greedy and selfish things though such behaviors were more condemned(谴责) then. But we cannot ignore the fact that people in the past lived a relatively more isolated life and faced less pressure compared with their modern twins.

Are we happier to share with others and be generous to them? There is no fixed answer either. Some people take great pleasure helping and giving to others while others feel happy doing the opposite. But I personally think that people should not be too selfish. Caring for others can actually encourage the development of a mutually beneficial relationship.

In conclusion, modern people appear to be more self-centered than those in the past due to strong outside pressure. However, we should encourage people to know the importance of being caring and generous and to build a mutually beneficial relationship with others.

Title: Are Modern People Becoming More Selfish?

Main comparisons	Contexts
	In the past people put caring, sharing and generosity in the (2)_________ place.
Nowadays, people seem to be more (3)_________ about themselves.
	People in the past appeared to be modest and self-effacing(谦让).
People may strive to achieve their own (5)_________, even at the price of their coworkers.
The author’s understanding
(6)_________ for the changes in author’s eyes	Fierce (7)_________ and great (8)_________ on modern people may be responsible for the changes.
The author’s (9)_________ towards topic	A relationship which can (10)_________ both sides should be established.

 

Nowadays people are troubled by the violence that spreads throughout the media. Movies, television and video games are full of gunplay and bloodshed, and one might reasonably ask what’s wrong with a society that presents videos of violence as entertainment.

Viewing large amounts of violent television and video games may well contribute to violent behavior in certain individuals. The trouble comes when researchers downplay uncertainties in their studies or overstate the case for causality（因果关系）. Skeptics were dismayed several years ago when a group of societies including the American Medical Association tried to end the debate by issuing a joint statement: “At this time, well over 1,000 studies… point to a causal connection between media violence and aggressive behavior in some children.”

Freedom-of-speech advocates accused the societies of catering to politicians, and even disputed the number of studies (most were review articles and essays, they said). When Jonathan Freedman, a social psychologist at the University of Toronto, reviewed the literature, he found only 200 or so studies of television-watching and aggression. And when he weeded out “the most doubtful measures of aggression”, only 28% supported a connection.

The critical point here is causality. The alarmists say they have proved that violent media cause aggression. But the assumptions behind their observations need to be examined. When labeling games as violent or non-violent, should a hero eating a ghost really be counted as a violent event? And when experimenters record the time it takes game players to read “aggressive” or “non-aggressive” words from a list, can we be sure what they are actually measuring? The intention of the new Harvard Center on Media and Child Health to collect and standardize studies of media violence in order to compare their methodologies, assumptions and conclusions is an important step in the right direction.

Another appropriate step would be to tone down the criticism until we know more. Several researchers write, speak and testify quite a lot on the threat posed by violence in the media. That is, of course, their privilege. But when doing so, they often come out with statements that the matter has now been settled, drawing criticism from colleagues. In response, the alarmists accuse critics and news reporters of being deceived by the entertainment industry. Such clashes help neither science nor society.

Why is there so much violence shown in movies, TV and video games?

A. Showing violence is thought to be entertaining.

B. Something has gone wrong with today’s society

C. Many people are fond of gunplay and bloodshed.

D. There is a lot of violence in the real world today.

What is the skeptics’ view of media violence?

A. Violence on television is fairly accurate reflection of real-world life.

B. Most studies exaggerate (夸大) the effect of media violence on the viewers.

C. A causal relationship exists between media and real-world violence.

D. The influence of media violence on children has been underestimated.

The author uses the term “alarmists” to refer to those who _________.

A. use standardized measurements in the studies of media violence

B. initiated the debate over the influence of violent media on reality

C. insist on a direct link between violent media and aggressive behavior

D. use appropriate methodology in examining aggressive behavior

The underlined phrase “weeded out” in Paragraph 3 most probably means _________.

   A. got rid of things that are not good     B. removed unwanted parts from something

   C. picked out things that are useful        D. took away unnecessary details of a report

What does the writer think of the debate concerning the relationship between the media and violence?

A. He more than agrees with the views held by the alarmists. 

B. It should come to an end since the matter has now been settled.

C. The past studies in this field have proved to be misleading.

D. More studies should be conducted before conclusions are drawn.

Nowadays people sometimes separate their waste to make it easier for it _______.

    A. reusing        B. to reuse       C. to be reused    D. reused