Imagine putting a seed in a freezer,waiting 30,000 years,and then taking the seed out and planting it. Do you think a flower would grow?
Amazingly, scientists have just managed to do something very similar. They found the fruit of an ancient plant that had been frozen underground in Siberia—a region covering central and eastern Russia—for about 31,800 years. Using pieces of the fruit,the scientists grew plants in a lab. The new blooms have delicate white petals. They are also the oldest flowering plants that researchers have ever revived from a deep freeze.
“This is like regenerating a dinosaur from tissues of an ancient egg,’’said Jane Shen-Miller,a biologist of University of California,Los Angeles.
The plant has a long history. Back when mammoths and woolly rhinoceroses walked on the land, an Arctic ground squirrel buried seeds and fruits in an underground chamber near the Kolyma River in northeastern Siberia. The ground became pennafrost, a layer of soil that stays frozen for a long time.
Recently, Russian scientists dug out the old squirrel hole and found the plant remains 38 meters below the surface. Back at the lab, the team fed nutrients to tissue from three of the fruits to grow shoots. Then the scientists transferred the shoots to pots filled with soil. The plants produced seeds that could be used to grow even more of them.
It’s important for scientists to know that plant tissues can still be revived after being frozen for a long time. That’s because many researchers are trying to preserve the seeds of modem plants by freezing them and then storing them in giant lockers at various spots around the globe. One such endeavor,an underground facility in Norway,is called the Svalbard Global Seed Vault. It stores hundreds of thousands of frozen seeds. If a plant ever goes extinct, scientists could bring it back by taking its seeds from the Svalbard or other storage lockers.
“No one knows how long they are able to live for,but freezing is basically the format for many plant conservation attempts nowadays,’’Jane Shen-Miller said. It’s a good thing that at least some plants are tough enough to survive in the experience.
1.Which of the following was NOT used to recreate the ancient plant?
A. Modem nutrients.
B. Parts of the fruits.
C. Its frozen seeds.
D. Plant pots with soil.
2.Why are scientists interested in this discovery?
A. It helps them learn how plant life has changed in the past 30,000 years.
B. It can help guide future efforts to protect endangered plants’ life.
C. It can provide directions for where to look for other ancient plants.
D. It proves that all plant life can survive for thousands of years when frozen.
3.The underlined word "they", in the final paragraph refers to .
A. plants
B. seeds
C. scientists
D. storage lockers
4.The purpose of the passage is to .
A. discuss a plant conservation effort
B. introduce some ancient plants
C. outline some causes of global warming
D. describe a scientific research project
高二英语阅读理解困难题
Imagine putting a seed in a freezer,waiting 30,000 years,and then taking the seed out and planting it. Do you think a flower would grow?
Amazingly, scientists have just managed to do something very similar. They found the fruit of an ancient plant that had been frozen underground in Siberia—a region covering central and eastern Russia—for about 31,800 years. Using pieces of the fruit,the scientists grew plants in a lab. The new blooms have delicate white petals. They are also the oldest flowering plants that researchers have ever revived from a deep freeze.
“This is like regenerating a dinosaur from tissues of an ancient egg,’’said Jane Shen-Miller,a biologist of University of California,Los Angeles.
The plant has a long history. Back when mammoths and woolly rhinoceroses walked on the land, an Arctic ground squirrel buried seeds and fruits in an underground chamber near the Kolyma River in northeastern Siberia. The ground became pennafrost, a layer of soil that stays frozen for a long time.
Recently, Russian scientists dug out the old squirrel hole and found the plant remains 38 meters below the surface. Back at the lab, the team fed nutrients to tissue from three of the fruits to grow shoots. Then the scientists transferred the shoots to pots filled with soil. The plants produced seeds that could be used to grow even more of them.
It’s important for scientists to know that plant tissues can still be revived after being frozen for a long time. That’s because many researchers are trying to preserve the seeds of modem plants by freezing them and then storing them in giant lockers at various spots around the globe. One such endeavor,an underground facility in Norway,is called the Svalbard Global Seed Vault. It stores hundreds of thousands of frozen seeds. If a plant ever goes extinct, scientists could bring it back by taking its seeds from the Svalbard or other storage lockers.
“No one knows how long they are able to live for,but freezing is basically the format for many plant conservation attempts nowadays,’’Jane Shen-Miller said. It’s a good thing that at least some plants are tough enough to survive in the experience.
1.Which of the following was NOT used to recreate the ancient plant?
A. Modem nutrients.
B. Parts of the fruits.
C. Its frozen seeds.
D. Plant pots with soil.
2.Why are scientists interested in this discovery?
A. It helps them learn how plant life has changed in the past 30,000 years.
B. It can help guide future efforts to protect endangered plants’ life.
C. It can provide directions for where to look for other ancient plants.
D. It proves that all plant life can survive for thousands of years when frozen.
3.The underlined word "they", in the final paragraph refers to .
A. plants
B. seeds
C. scientists
D. storage lockers
4.The purpose of the passage is to .
A. discuss a plant conservation effort
B. introduce some ancient plants
C. outline some causes of global warming
D. describe a scientific research project
高二英语阅读理解困难题查看答案及解析
Imagine that someone in your neighborhood broke the law, and the judge put the whole neighborhood under suspicion. How fair will that be? Well, it happens every day to high schoolers. Just because some students have stolen things in shops, all of us are treated like “shoplifters”. Even though I’d never steal, store employees looked at me like I’m some kind of hardened criminal mastermind.
For example, during one lunch period, my friend Denny and I went to the Grab “n” Go on Tuesday. We arrived to find a line of students waiting outside. A new sign in the window told the story:“ NO MORE THAN TWO STUDENTS AT A TIME.” After 15 minutes, we finally got in. But the store manger laid the evil eye on us. I asked him about the new sign, and he said, “You kids are lifting too much stuff.” You kids? Too much stuff? Not only were we considered to be shoplifters, but brilliant, greedy shoplifters.
The Grab “n” Go isn’t an isolated case. Earlier this year, a department store worker told me to leave my backpack at the front of the store. When I asked who was going to keep an eye on my stuff, she said, “Don’t worry. It isn’t going anywhere.” In other words, I had to risk losing my stuff so that the store wouldn’t have to risk losing theirs. “Don’t worry,” I replied, “I don’t need to shop here.”
The most annoying thing, though, is the way employees watch my friends and me. It’s almost strange and frightening. Once, at a drug store, I went down an aisle and found a guy standing on a box, stocking the shelves. He was watching my hands, which were empty. He got down off his box and rushed off, as if he was going to get the store manger. How crazy is that?
You know, this kind of prejudice can go both ways. I work at the CD Crib, and every day I see adults commit a terrible crime. They put on a set of headphones and sort of dance to the music. Talk about bad! Tomorrow, I’m going to put a sign in the window: “ NO MORE THAN TWO ADULTS LISTNENING TO MUSIC AT A TIME.”
1.“ Shoplifters” ( Paragraph 1) refers to _____________.
A. the neighbor B. thieves
C. employees D. store owners
2.The manager of the Grab “n” Go thought that _______________________.
A. people might be angry about the lining up
B. the shop might be over-crowded
C. students might steal things
D. kids should be accompanied by their parents
3.What is the tone of the writer?
A. Angry B. Sad
C. Pleased D. Excited
4.By saying “this kind of prejudice can go both ways”, the writer intends to _______________.
A. put up a notice to prevent adults from committing a crime.
B. encourage adults to listen to CDs before they buy them.
C. stop adults from talking bad things when in CD stores.
D. accuse adults in the same way as they did towards the boys
5. How does the writer develop his argument?
A. By example B. By classification
C. By comparison and contrast D. By cause and effect
高二英语阅读理解中等难度题查看答案及解析
Elizabeth’s Second!
In 60 years, the Queen has never put a foot wrong in public. And for the last 24 of them, it turns out she’s had a secret weapon — the nice Ella Slack. The former BBC manager has, unknown to anyone except a handful of key advisers, spent the last quarter of a century acting as the Queen’s official stand-in at rehearsals (排练) for royal events. The 69-year-old has never accepted a penny for her royal service, considering it “a pleasure and an honour” to ensure that everything runs smoothly for the Queen. “How many people in the world have had a chance to sit in a royal landau (马车) or walk onto the dais (讲台) at Windsor Castle even before the Queen has done so?” she said.
While Miss Slack may not resemble the Queen facially, she has a similar figure to the Queen, standing just 5 foot. The Queen is 5 foot 2 inch. She began her remarkable role in 1988, when she was working as manager of the BBC’s sports and events department. A producer asked her if she could stand in for the Queen to check camera angles at a rehearsal — and her second career was born.
Since then, from the State Opening of Parliament (议会) to the 50th anniversary of Victory day, wherever the Queen is on duty Miss Slack is likely to have been there first. She has perfected her own version of the Queen’s clothes, including a black patent handbag she bought in a charity shop for ￡1, and even styles her hair like the Queen.
1.What’s the Queen’s secret weapon?
A. She often meets people in public.
B. She actively attends social activities.
C. She has a nice lady to act as herself.
D. She and Miss Slack have a lot in common.
2.Miss Slack’s words in Paragraph 1 indicate that ___________.
A. she thinks the job honorable and worthy
B. she thinks she can do the job better
C. she thinks frequently of her role
D. she is determined to carry the job on
3.How did Miss Slack get the job?
A. The Queen invited her to do so.
B. The BBC appointed her to finish the job.
C. She was invited to have an accidental try.
D. The advisers offered her the chance.
4.In which section of a newspaper may you find the passage?
A. Education. B. Entertainment.
C. Sports. D. Health.
高二英语阅读理解中等难度题查看答案及解析
Elizabeth’s Second!
In 60 years, the Queen has never put a foot wrong in public. And for the last 24 of them, it turns out she’s had a secret weapon — the nice Ella Slack. The former BBC manager has, unknown to anyone except a handful of key advisers, spent the last quarter of a century acting as the Queen’s official stand-in at rehearsals (排练) for royal events. The 69-year-old has never accepted a penny for her royal service, considering it “a pleasure and an honour” to ensure that everything runs smoothly for the Queen. “How many people in the world have had a chance to sit in a royal landau (马车) or walk onto the dais (讲台) at Windsor Castle even before the Queen has done so?” she said.
While Miss Slack may not resemble the Queen facially, she has a similar figure to the Queen, standing just 5 foot. The Queen is 5 foot 2 inch. She began her remarkable role in 1988, when she was working as manager of the BBC’s sports and events department. A producer asked her if she could stand in for the Queen to check camera angles at a rehearsal — and her second career was born.
Since then, from the State Opening of Parliament (议会) to the 50th anniversary of Victory day, wherever the Queen is on duty Miss Slack is likely to have been there first. She has perfected her own version of the Queen’s clothes, including a black patent handbag she bought in a charity shop for ￡1, and even styles her hair like the Queen.
1.What’s the Queen’s secret weapon?
A. She often meets people in public.
B. She actively attends social activities.
C. She has a nice lady to act as herself.
D. She and Miss Slack have a lot in common.
2.Miss Slack’s words in Paragraph 1 indicate that ___________.
A. she thinks the job honorable and worthy
B. she thinks she can do the job better
C. she thinks frequently of her role
D. she is determined to carry the job on
3.How did Miss Slack get the job?
A. The Queen invited her to do so.
B. The BBC appointed her to finish the job.
C. She was invited to have an accidental try.
D. The advisers offered her the chance.
4.In which section of a newspaper may you find the passage?
A. Education. B. Entertainment.
C. Sports. D. Health.
高二英语阅读理解中等难度题查看答案及解析
Write a winning story!
You could win ￡1,000 in this year’s Fiction Prize and have your story printed in Keep Writing magazine. Ten other lucky people will win a cheque for ￡100.
Once again, we need people who can write good stories. The judges, who include Mary Littlejohn, the novelist, Michael Brown, the television reporter, and Susan Hitchins, the editor of Keep Writing, are looking for interesting and original stories. Detective fiction was extremely popular last year, although the competition winner produced a love story. You can write down about whatever you want but here’s some advice to start your thinking:
Write about what you know
This is the advice which every writer should pay attention to and, last year, nearly everyone who wrote for us did exactly that. Love, family, problems with friends ---- these were the main subjects of the stories. However, you need to turn ordinary situations into something interesting that people will want to read about. Make the reader want to continue reading by writing about ordinary things in a new and surprising way.
Get your facts right
It’s no good giving a description of a town or explaining how a jet engine works if you get it wrong. So avoid writing anything unless you’re certain about it.
Hold the reader’s attention
Make the beginning interesting and the ending a surprise. There is nothing worse than a poor ending. Develop the story carefully and try to think of something unusual happening at the end.
Think about the characters
Try to bring the people in your story alive for the reader by using well-chosen words to make them seem real.
Your story must be your own work, between 2,000 and 2,5000 words and typed, double-spaced, on one side only of each sheet of paper.
Even if you’re in danger of missing the closing date, we are unable to accept stories by fax or email. You must include the application form with your story. Unfortunately your story cannot be returned, nor can we discuss our decisions.
You should not have had any fiction printed in any magazine or book in this country ---- a change in the rules by popular request ---- and the story must not have happened in print or in recorded form, for example on radio or TV, anywhere in the world.
Your fee of ￡5 will go to the Writers’ Association. Make your cheque payable to Keep Writing and send it with the application form and your story to:
Keep Writing
75 Broad Street Birmingham
B12 4TG
The closing date is 30 July and we will inform the winner within one month of this date. Please note that if you win, you must agree to have your story printed in our magazine.
1.How should writers deal with ordinary situations while writing?
A. They should make them appealing to readers.
B. They should copy others’ ideas.
C. They should change some facts to make them interesting.
D. They should describe them as they are.
2.What shouldn’t a writer do?
A. Making the contents interesting. B. Getting the facts right.
C. Meeting the deadline. D. Making the end ordinary.
3.Writers should present their works in the following ways except that ____________.
A. they should write originally
B. they can type their stories as they like
C. they should follow some rules
D. they should hand in their stories in time
4.Which of the following is TRUE according to the passage?
A. Late stories can be faxed if necessary.
B. Entry needs no fee.
C. Winners can have their stories printed in other magazines.
D. All stories should be presented by mail.
高二英语阅读理解中等难度题查看答案及解析
A little more than 30 years ago, a teenager named Jadav “ Molai” Payeng began burying seeds along a barren sandbar(沙洲)near his birthplace in northern India’s Assam. Not long after that, he decided to dedicate(献身) his life to this effort, so he moved to the site in order that he could work full-time creating a new forest ecosystem. Unbelievably, the spot today hosts a sprawling(蔓延的) 1360 acres of jungle that Payeng single-handedly planted.
The Times of India recently caught up with Payeng in his remote forest cottage to learn more about how he came to leave such an unbelievable mark on the landscape.
It all started way back in 1979, when floods washed a large number of snakes ashore on the sandbar. One day after the floods, Payeng, only 16 then, found the place dotted with the dead snakes. That was the turning point of his life.
“The snakes died in the heat without any tree cover. I sat down and wept over their lifeless bodies. I asked the forest department if they could grow trees there. They said nothing would grow there. Instead, they asked me to try growing bamboo. It was painful, but I did it .There was nobody to help me. Nobody was interested,” says Payeng, now 47.
While it’s taken years for Payeng’s remarkable dedication to planting to receive some well-deserved recognition internationally, it didn’t take long for wildlife in the region to benefit from the forest. Demonstrating a keen understanding of ecological balance, Payeng even transplanted ants to his ecosystem to maintain its natural harmony .Soon the shadeless sandbar was transformed into a natural ecosystem. The forest, called the Molai woods, now serves as a safe habitat for numerous birds, deer, rhinos, tigers and elephants.
Despite Payeng’s outstanding project, forestry officials in the region first learned of this new forest in 2008, and since then they’ve come to recognize his efforts as truly remarkable, but perhaps not enough.
“We’re amazed at Payeng,” says Gunin Saikia, Assistant Conservator of Forests. “He has been at it for 30 years .Had he been in any other country, he would have been made a hero.”
1.Payeng moved to the barren sandbar to ________________.
A.make a living there B.plant trees to improve the environment
C.do some research D.look after the 1360 acres’ jungle
2.It can be concluded that the interview in the report above was conducted in _________.
A.1979 B.2008 C.2010 D.2012
3.Which of the following statements is TRUE according to the passage?
A.Payeng got a lot of help from the forest department at the beginning.
B.It took quite a long time for Payeng’s dedication to be recognized.
C.Payeng earned his fame by transplanting ants to his ecosystem.
D.The Molai woods now is used as a zoo to attract Indian tourists.
4.The underlined sentence implies that _______________.
A.Payeng should be honored as a great hero in India
B.Payeng has been a great hero in other countries
C.other countries should not make Payeng a hero
D.India made Payeng a hero earlier than other countries
高二英语阅读理解中等难度题查看答案及解析
In China, the history of people planting and using bamboo can date back to as far as 7,000 years. As early as the Shang Dynasty, bamboo was being used in ancient people’s daily lives. It was used for food, clothing, housing, transportation, 1. (music) instruments and even weapons.
The 2. (apply) of bamboo in science and technology is thrilling. In 251 BC, Li Bing, in Sichuan, 3. (lead) the local people in building the Dujiang Weirs(都江堰), the first irrigation network in the world, in which bamboo played 4. important role. The world’s oldest water pipe was also 5. (make) of bamboo. During the Han Dynasty, the people in Sichuan 6. (success) sank a 1600-metre-deep well with thick bamboo ropes. This technology did not spread to Europe 7. the 19th century, and it was by using the technology 8. the Americans drilled the first oil well in Pennsylvania in 1859.
In Chinese culture, bamboo is well-known as 9. of the “four gentlemen” in plants. To many famous men, bamboo is a symbol of goodness and honesty. It is always closely related to people of positive spirits. Bamboo culture contributes to encouraging people to hold on when 10. (face) tough situations.
高二英语语法填空中等难度题查看答案及解析
Some 30,000 years ago, artists who lived in caves in Europe painted pictures of the animals around them: panthers, hyenas, rhinos, cave lions, mammoths and other creatures which have been extinct for a long time.
The artwork, more than a thousand drawings, is considered the oldest group of human cave drawings which have ever been discovered. They were preserved because the cave was sealed---closed off--for more or less 23,000 years.
Fast forward to December 18, 1994, a group of French cave scientists were exploring caves in southern France. Jean Marie Chauvet, who led the group then, describes the process of discovering the cave paintings. “At that time I was in the front, Eliette just walked behind me, Christian behind. Eliette said she saw two marks with red ochre(赭石) and she said, ‘They came here.’ And at this very moment everything began. The drawings and everything linked to the parietal art(壁画). That is where it started.”
Cave art expert Jean Clotttes reviewed the paintings. “I was amazed at the number of paintings there were and paintings of their quality and particularly in front of the panel of the horses.”
Scientific analysis confirmed the prehistoric date of the artwork. Studies showed the drawings were created tens of thousands of years ago, before human history was written. The United Nations’ cultural agency UNESCO lists the cave as a World Heritage Site. They say that the drawings form a remarkable expression of early human artistic creation of grand excellence and variety.
The Chauvet Cave has been named after the explorer who first entered it. However, its environment and drawings are too fragile to be visited by human beings. So the cave is closed, and only people there for scientific purposes can go inside and see the artwork.
However, French authorities asked experts to create an exact copy of the cave, called Pont d’Arc Cavern. The copy, which we also called replica, cost more than 59 million dollars to build. It opened at the end of April in France.
Pascal Terrasse is the president of the cavern. He says everyone will be able to experience the thrill of looking at drawings made by the first humans in Europe. He says the place is magic because it is done so well. Authorities say they think as many as 400,000 people will be allowed to visit Pont d’Arc Cavern every year.
1.According to Jean Clottes’ words in Paragraph 4, the paintings in the cave were .
A. abstract B. superior C. creative D. inspiring
2.Which of the follow statements is TRUE about the Chauvet Cave?
A. It was closed off for more than 30,000 years.
B. It is thought to be the origin of modern parietal art.
C. The environment and artwork there are very easy to damage.
D. The majority of drawings there are about the extinct animals.
3.The purpose of creating Pndt d’Arc Cavern is to .
A. show admiration for the earliest artists in Europe
B. arouse visitors’ awareness of protecting ancient art
C. offer visitors chances to view the wonderful artwork
D. collect money for the perseverance of the Chauvet Cave
高二英语阅读理解中等难度题查看答案及解析
Some 30,000 years ago, artists who lived in caves in Europe painted pictures of the animals around them: panthers, hyenas, rhinos, cave lions, mammoths and other creatures which have been extinct for a long time. The paintings were highly realistic. Some even showed movement.
The artwork, more than a thousand drawings, is considered the oldest group of human cave drawings which have ever been discovered. They were preserved because the cave was sealed---closed off--for more or less 23,000 years.
Fast forward to December 18, 1994, a group of French cave scientists were exploring caves in southern France. Jean Marie Chauvet, who led the group then, describes the process of discovering the cave paintings. “At that time I was in the front, Eliette just walked behind me, Christian behind. Eliette said she saw two marks with red ochre and she said, ‘They came here.’ And at this very moment everything began. The drawings and everything linked to the parietal art(壁画). That is where it is tarted.”
Cave art expert Jean Clotttes reviewed the paintings. “I was amazed at the number of paintings there were and paintings of their quality and particularly in front of the panel of the horses.”
Scientific analysis confirmed the prehistoric date of the artwork. Studies showed the drawings were created tens of thousands of years ago, before human history was written. The United Nations’ cultural agency UNESCO lists the cave as a World Heritage Site. They say that the drawings form a remarkable expression of early human artistic creation of grand excellence and variety.
The Chauvet Cave has been named after the explorer who first entered it. However, its environment and drawings are too fragile to be visited by human beings. So the cave is closed, and only people there for scientific purposes can go inside and see the artwork.
However, French authorities asked experts to create an exact copy of the cave, called Pont d’Arc Cavern. The copy, which we also called replica, cost more than 59 million dollars to build. It opened at the end of April in France.
Pascal Terrasse is the president of the cavern. He says everyone will be able to experience the thrill of looking at drawings made by the first humans in Europe. He says the place is magic because it is done so well. Authorities say they think as many as 400,000 people will be allowed to visit Pont d’Arc Cavern every year.
1.According to Jean Clottes’ words in Paragraph 4, the paintings in the cave were .
A.abstract B. superior C. creative D. inspiring
2.Which of the follow statements is TRUE about the Chauvet Cave?
A.It was closed off for more than 30,000 years.
B.It is thought to be the origin of modern parietal art.
C.The environment and artwork there are very easy to damage.
D.The majority of drawings there are about the extinct animals.
3.The purpose of creating Pndt d’Arc Cavern is to .
A.show admiration for the earliest artists in Europe
B.arouse visitors’ awareness of protecting ancient art
C.offer visitors chances to view the wonderful artwork
D.collect money for the perseverance of the Chauvet Cave
高二英语阅读理解中等难度题查看答案及解析
In the last 30 years, the Make-A-Wish Foundation has granted nearly 300,000 wishes worldwide to children battling life-threatening illnesses, throwing light on worlds darkened by diseases and bringing hope to children and their families.
With a foreword（序）by Make-A-Wish cofounder Frank Shankwitz, Once Upon A wish shares the wishes and stories of eight children. These families generously invite us into their worlds, allowing us to become part of their darkest moments, their unimaginable realities, their greatest hopes, deepest fears, and unbelievable successes.
Experience the story of Katelyn, a little girl, becoming a medical marvel（奇迹）after lighting all the odds stacked against her and making it her life-long goal to raise $3 million for St. Jude Hospital; read about a wheelchair-bound boy, Garrett, giving the gift of mobility to disabled Cambodian men and women; cheer for a little boy, Dakota, who collects millions of pennies each year to help others fight the disease he once fought. Become inspired and forever-changed by the generosity, hope, courage, and optimism of these children and their families and experience the power of two words - I wish.
Once Upon A Wish is a celebration of hope, revealing how wishes-come-true can become motivators and cherished gifts that will last a lifetime.
Price: $9.99
Where to download: Available on the iPhone , iPad , iPod touch, and Mac.
Category: Biographies & Memoirs
Published: Mar 05, 2013
Publisher: BenBella Books, Inc.
Seller: The Perseus Books Group, LLC
Print Length: 352 Pages
Language: English
1.We can learn that the Make-A-Wish Foundation____.
A. was set up in the early 1990s.
B. was set up to help poor people all over the world.
C. aims at helping severely sick children fulfill their wishes.
D. mainly offers free treatment to severely sick children.
2.What is Once Upon A Wish mainly about?
A. The history of the Make-A-Wish Foundation.
B. Wishes and stories of eight children.
C. Some children's experiences of helping others.
D. Frank Shankwitz's personal experiences with some children.
3.Dakota spends the money he collects in helping____.
A. to set up St. Jude Hospital .
B. people infected with AIDS.
C. disabled Cambodians move around .
D. those who are fighting the same disease as he once had.
高二英语阅读理解中等难度题查看答案及解析