Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color.
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 color of a dark-striped zebrafish（斑马鱼） to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebrafish skin color is determined by pigment cells, which contain melanin (黑色素). The number, size and darkness of melanin per pigment cell determine skin color.
It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation (变异) in the gene for melanin 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 color, said Cheng.
The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson. The passage mainly tells us that ________.
| A．people can not change their skin color without any pain |
| B．the new discovery could lead to research into ways to change skin color safely |
| C．pop king Michael Jackson often changed his skin color as he liked |
| D．scientists have found out that people’s skin color is determined by the gene |
It can be inferred from the passage that ________.
| A．nowadays people who want to change their skin color 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 |
Scientists have done an experiment on a dark-striped zebrafish in order to ________.
| A．find the different genes of humans’ |
| B．prove the humans’ skin color is determined by the pigment gene |
| C．find out the reason why the Africans’ skin color is dark |
| D．find out the ways of changing people’s skin color |
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 gene for melanin production |
| C．they have fewer activities outside |
| D．they pay much attention to protecting their skin |
The writer’s attitude towards the discovery is ________.
| A．neutral（中立的） | B．negative | C．positive | D．indifferent（冷漠） |
(D) Only two countries in the advanced world provide no guarantee for paid leave from work to care for a newborn child．Last spring one of the two，Australia，gave up the bad distinction by setting up paid family leave starting in 2011．I wasn’t surprised when this didn’t make the news here in the United States—we’re now the only wealthy country without such a policy．
The United States does have one explicit family policy，the Family and Medical Leave Act，passed in 1993．It entitles workers to as much as 12 weeks’ unpaid leave for care of a newborn or dealing with a family medical problem．Despite the modesty of the benefit，the Chamber of Commerce and other business groups fought it bitterly，describing it as “government-run personnel management” and a “dangerous precedent（先例）．” In fact，every step of the way，as (usually) Democratic leaders have tried to introduce work-family balance measures into the law，business groups have been strongly opposed．
As Yale law professor Anne Alstott argues，justifying parental support depends on defining（定义）the family as a social good that，in some sense，society must pay for．Parents are burdened in many ways in their lives: there is “no exit” when it comes to children．Society expects—and needs—parents to provide their children with continuity of care．And society expects—and needs—parents to persist in their roles for 18 years，or longer if needed．
What do we learn about paid family leave according to Paragraph 1？
| A．It came as a surprise when Australia adopted the policy． |
| B．Setting up this policy made Australia less influential． |
| C．It has now become a hot topic in the United States． |
| D．No such policy is applied in the United States． |
What makes it hard to take work-family balance measures in the States？
| A．The incompetence of the Democrats． |
| B．The opposition from business circles． |
| C．The lack of a precedent in American history． |
| D．The existing Family and Medical Leave Act． |
What is Professor Anne Alstott’s argument for parental support？
| A．Children need continuous care． |
| B．Good parenting benefits society． |
| C．The cost of raising children has been growing． |
| D．The U．S．should keep up with other developed countries． |
Why is the author against classifying parenting as a personal choice？
| A．Parenting is regarded as a moral duty． |
| B．Parenting relies largely on social support． |
| C．Parenting produces huge moral benefits． |
| D．Parenting is basically a social responsibility． |
(C)
The Loss of Innocence
Innocence is such a precious gift．It’s explained as freedom from guilt or wrong doing．Just imagine never having to worry about anything and having a guilt free mind．Some people wish to save this kind of innocence from being lost from childhood to adulthood．
What would the world be like if innocence were never lost？One way it would benefit humanity is the lack of hatred （仇恨）among the world．During youth，there may be an occasional argument，even a little physical fight，but nothing like firing a handgun at a fellow human being．And children are blind towards the racial differences of others．A kid will hang out with any other kid．It is the lack of innocence and the ignorance we learn from adults that influence children otherwise．Another benefit is the constant desire for fun and adventure．With very little if any time at all for fun，the adventurous mind is lost in time with the responsibilities placed upon adults．If innocence were kept alive，these ambitions would never depart from our lives．
However，other people actually hate the idea of innocence lasting forever．They feel that the lack of organization and mental power of those with innocence would cause extremely destructive consequences to society in general．A large number of individuals would never have the urge to learn，work，and act upon the necessary needs for humanity to survive．Without a proper education which is usually provided by those who no longer live in a world of innocence，people would not have the desire to succeed，get a good job in life，or provide income for their families，which would hurt the lives of children．
The lack of a good education and career would also harm the economy．As long as innocence is kept alive，no one would be terribly angered at the lack of effort people put out in the workplace，resulting in a strong decline in production and quality of needed goods．
Maybe it is wrong in wanting to save innocence．It sure is a nice thought，though．Perhaps innocence was meant to be lost．It was god’s will to make things the way they are，and there is a good purpose for everything．All that remains to be said about innocence is to enjoy it while it lasts．The author believes that the loss of innocence in adulthood should be _______．
| A．avoided |
| B．condemned |
| C．accepted |
| D．inspired |
Lifelong innocence would be beneficial to society in that _______．
| A．proper education would be provided |
| B．there would be no racial discrimination |
| C．more happy families would be guaranteed |
| D．people would realize their childhood dreams |
According to the author，people with innocence can hurt the economy with their lack of _____．
| A．motivational will |
| B．mental ability |
| C．adventurous ambitions |
| D．needed goods |
Which of the following shows the structure of the passage？
A． |
B． |
C． |
D． |
(B)
Lights Out at Bedtime
There are plenty of good reasons to power up a personal desktop or laptop computer in the evening — writing e-mails，chatting on social networks or making purchases over the Internet，for instance．But various studies indicate that people who stare at a PC’s bright monitor shortly before going to bed probably sleep less soundly than they would otherwise because the light seriously affects their natural wake-sleep cycle．"They haven't proved it though，" says Dieter Kunz，the team's director at Charite's Psychiatric Clinic in St．Hedwig's Hospital in Berlin．
Similarly，exposure to just 10 minutes of normal bathroom lighting is enough to free the sleep hormone melatonin，which regulates people's natural wake-sleep cycle and makes them sleepy at nightfall．
Ten years ago，a team of British and American researchers detected a photo-pigment（光敏色素） in the human eye that signals to the body whether it is day or night，summer or winter．The photo-pigment is especially sensitive to blue light．
"The blue light more or less tells the body，'It's daytime，be awake，'" Kunz says．Monitors have a mostly cold white light content and scientists suspect the photo-pigment may react similarly to it．So the longer people look into the bright light，the more awake they become - and then sleep poorly．
A lot of people have difficulty "switching off" in the evening．About half of the women in Germany and a quarter of the men sleep poorly．
Environmental factors are only one of the possible causes．Job stress as well as personal and health concerns are also the main reasons for their sleep problems．
In addition，electronic objects' standby lights and indicator lamps can be annoying in the dark and affect sleep．"Sound scientific evidence is still lacking on this matter，" Kunz notes．
According to Kunz，those who cannot go without their computer in the evening should turn down the blue content if possible and lower the brightness somewhat．"But nobody does that because，after all，you want to concentrate while working at the computer and the light helps the brain．"The passage is mainly about ____________．
| A．natural wake-up cycles |
| B．the effect of light on sleep |
| C．personal and health concerns |
| D．functions of computer monitors |
The underlined word “which” in Paragraph 2 refers to_____．
| A．normal bathroom lighting |
| B．10-minute exposure to lighting |
| C．the release process of a chemical |
| D．a chemical affecting one’s sleep cycle |
We can learn from the passage that ______．
| A．the blue light has a calming effect． |
| B．the photo-pigment tells people day or night |
| C．women in Germany use computers more often than men |
| D．it has been proved that standby lights affect people’s sleep |
阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
(A)
I had to knock on the taxi to get his attention．Finally，the driver，a man about 60，looked up from behind the wheel and apologized，“I’m sorry，but I was reading a letter．” He sounded as if he had a cold or a cough．
Since I was in no hurry，I told him to finish his letter．He shook his head，explaining that he had already read it several times and almost knew it by heart．Curious，I asked whether it was from a child or maybe a grandchild．“This isn’t family，”he replied．“though he might just as well have been a regular member of the family．Old Ed and I grew up together．”
They were always friends．But since he moved away from the neighborhood 30 years ago，it’d generally just been postcards at Christmas time between them．A couple of weeks ago，Ed died．“I should have kept in touch．” He repeated this，more to himself than to me．To comfort him，I said sometimes we just didn’t seem to find the time．“But we used to find the time，” he said．“Take a look．” He handed the letter over to me．
The first sentence “I’ve been meaning to write for some time，but I’ve always delayed it．” reminded me of myself．It went on to say that he often thought about the good times they had had together．When I read the part where it said “Your friendship really means a lot to me，more than I can say because I’m not good at saying things like that”，I found myself nodding in agreement．
We had gone several kilometers and were almost at my hotel, so I read the last paragraph: “So I thought you’d like to know that I was thinking of you.” And it was ended with “Your Old Friend, Tom.”
“I thought your friend’s name was Ed,” I said.
“I’m Tom,” he explained. “It’s a letter I wrote to Ed before I knew he’d died. I never put it in the mailbox. I guess I should have written it sooner.” His face was pale as he wiped his eyes with a handkerchief.
When I got to my hotel room I didn’t unpack right away．I had to write a letter and post it．Who wrote the letter？
| A．Tom |
| B．Old Ed． |
| C．The author． |
| D．The driver’s grandchild． |
It can be inferred from the passage that the driver regretted_____．
| A．missing Ed’s funeral |
| B．moving away from his neighborhood |
| C．forgetting to send Ed Christmas cards |
| D．not being able to keep in touch with Ed |
From Paragraph 4，we learn that the author _______．
| A．often fails to write to his friends |
| B．has no intention to write to his friends |
| C．had many great moments with his friends |
| D．was good at expressing his feelings to friends |
What message does the passage probably try to convey？
| A．Comfort your friends when they are feeling down． |
| B．Life is unpredictable so live each day as if it were your last． |
| C．Remember to always mail your letters after expressing your words． |
| D．Always make time to value and experience your lasting friendships． |
On a stormy day last August, Tim heard some shouting．Looking out to the sea carefully, he saw a couple of kids in a rowboat were being pulled out to sea.
Two 12-year-old boys, Christian and Jack, rowed out a boat to search a football．Once they’d rowed beyond the calm waters, a beach umbrella tied to the boat caught the wind and pulled the boat into open water．The pair panicked and tried to row back to shore．But they were no match for it and the boat was out of control.
Tim knew it would soon be swallowed by the waves.
“Everything went quiet in my head,” Tim recalls（回忆）．“I’m trying to figure out how to swim to the boys in a straight line.”
Tim took off his clothes and jumped into the water．Every 500 yards or so, he raised his head to judge his progress．“At one point, I considered turning back,” he says．“I wondered if I was putting my life at risk.” After 30 minutes of struggling, he was close enough to yell to the boys, “Take down the umbrella! Let’s aim for the pier（码头）,” Jack said．Tim turned the boat toward it．Soon afterward, waves crashed over the boat, and it began to sink．“Can you guys swim?” he cried．“A little bit,” the boys said.
Once they were in the water, Tim decided it would be safer and faster for him to pull the boys toward the pier．Christian and Jack were wearing life jackets and floated on their backs．Tim swam toward land as water washed over the boys’ faces.
“Are we almost there?” they asked again and again．“Yes,” Tim told them each time.
After 30 minutes, they reached the pier.
Why was the boat far into open water?
A．The boys rowed too fast．
B．The big current carried it.
C．The wind blew it．
C．The boys tried to get attention..
Why did the two boys go to the sea?
| A．To go boat rowing |
| B．To get back their football. |
| C．To swim in the open water |
| D．To test the umbrella as a sail. |
What does “it” in Paragraph 2 refer to?
| A．The beach |
| B．The water |
| C．The boat |
| D．The wind |
Why did Tim raise his head regularly?
| A．To take in enough fresh air |
| B．To consider turning back or not. |
| C．To check his distance from the boys． |
| D．To ask the boys to take down the umbrella. |
How can the two boys finally reach the pier?
| A．They were dragged to the pier by Tim. |
| B．They swam to the pier all by themselves. |
| C．They were washed to the pier by the waves. |
| D．They were carried to the pier by Tim on his back. |
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