Social networking websites are causing alarming changes in the brains of young users, a famous scientist has warned.Sites such as Facebook, Twitter and Bebo are said to shorten attention spans (幅度), encourage instant satisfaction and make children more self-centered.
Warnings from neuroscientist (神经系统科学家) Susan Greenfield will disturb the millions whose social lives depend on surfing their favorite websites each day.But they will strike a chord (弦) with parents and teachers who complain that many teenagers lack the ability to communicate or concentrate away from their screens.
More than 150 million use Facebook to keep in touch with friends, share photographs and videos and post regular updates of their movements and thoughts.A further six million have signed up to Twitter, the "micro-blogging" service that lets users exchange text messages about themselves.But while the sites are popular and extremely profitable, a growing number of psychologists and neuroscientists believe they may be doing more harm than good.
Baroness Tarot, an Oxford University neuroscientist believes repeated exposure could rewire the brain.Computer games and fast-paced TV shows were also a factor, she said."My fear is that these technologies are weakening the brain to the state of small children who are attracted by buzzing noises and bright lights, who have a small attention span and live for the moment." "I often wonder whether real conversation in real time may eventually give way to these easier and faster screen dialogues, in much the same way as killing and butchering an animal to eat has been replaced by the convenience of packages on the supermarket shelf," she said.
Psychologists have also argued that digital technology is changing the way we think.They point out that students no longer need to plan their term papers before starting to write—thanks to word processors they can edit as they go along.
A study by the Broadcaster Audience Board found teenagers now spend seven and a half hours a day in front of a screen.Educational psychologist Jane Healy believes children should be kept away from computer games until they are seven.Most games only excite the "flight or fight" areas of the brain, rather than the areas responsible reasoning.
Sue Palmer, author of Toxic Childhood, said: "We are seeing children's brain development damaged because they don't engage in the activity they have engaged in for thousands of years.I'm not against technology and computers.But before they start social networking, they need to learn to make real relationships with people."
1..
According to the passage, social networking websites might _____.
A.make young users more selfish
B.lengthen young users' attention span
C.encourage young users constant satisfaction
D.help young users communicate better with their families
2..
A neuroscientist may worry that sites like Facebook may ______.
A.help children learn to make real relationships with people in society
B.encourage students not to plan their term papers before starting to write
C.disturb those whose social lives depend on surfing their favorite websites
D.make real conversation in real time give way to easier and faster screen dialogue
3..
From the passage we can infer that _____.
A.Baroness Tarot agrees websites cause small children's small attention span
B.Jane Healy believes computer games can do good to children's reasoning
C.Susan Greenfield's warnings have been brought to wide public attention
D.Sue Palmer's book Toxic Childhood discusses the development of networking
4..
What is the purpose of this passage?
A.To tell us the conflict between neuroscientists and psychologists on websites.
B.To present some negative opinions on social networking websites.
C.To offer advice on the problem of brain damage caused by social networking.
D.To analyse how social networking websites cause damage in the brains of teenagers.
高二英语阅读理解简单题
Social networking websites are causing alarming changes in the brains of young users, a famous scientist has warned.Sites such as Facebook, Twitter and Bebo are said to shorten attention spans (幅度), encourage instant satisfaction and make children more self-centered.
Warnings from neuroscientist (神经系统科学家) Susan Greenfield will disturb the millions whose social lives depend on surfing their favorite websites each day.But they will strike a chord (弦) with parents and teachers who complain that many teenagers lack the ability to communicate or concentrate away from their screens.
More than 150 million use Facebook to keep in touch with friends, share photographs and videos and post regular updates of their movements and thoughts.A further six million have signed up to Twitter, the "micro-blogging" service that lets users exchange text messages about themselves.But while the sites are popular and extremely profitable, a growing number of psychologists and neuroscientists believe they may be doing more harm than good.
Baroness Tarot, an Oxford University neuroscientist believes repeated exposure could rewire the brain.Computer games and fast-paced TV shows were also a factor, she said."My fear is that these technologies are weakening the brain to the state of small children who are attracted by buzzing noises and bright lights, who have a small attention span and live for the moment." "I often wonder whether real conversation in real time may eventually give way to these easier and faster screen dialogues, in much the same way as killing and butchering an animal to eat has been replaced by the convenience of packages on the supermarket shelf," she said.
Psychologists have also argued that digital technology is changing the way we think.They point out that students no longer need to plan their term papers before starting to write—thanks to word processors they can edit as they go along.
A study by the Broadcaster Audience Board found teenagers now spend seven and a half hours a day in front of a screen.Educational psychologist Jane Healy believes children should be kept away from computer games until they are seven.Most games only excite the "flight or fight" areas of the brain, rather than the areas responsible reasoning.
Sue Palmer, author of Toxic Childhood, said: "We are seeing children's brain development damaged because they don't engage in the activity they have engaged in for thousands of years.I'm not against technology and computers.But before they start social networking, they need to learn to make real relationships with people."
1..
According to the passage, social networking websites might _____.
A.make young users more selfish
B.lengthen young users' attention span
C.encourage young users constant satisfaction
D.help young users communicate better with their families
2..
A neuroscientist may worry that sites like Facebook may ______.
A.help children learn to make real relationships with people in society
B.encourage students not to plan their term papers before starting to write
C.disturb those whose social lives depend on surfing their favorite websites
D.make real conversation in real time give way to easier and faster screen dialogue
3..
From the passage we can infer that _____.
A.Baroness Tarot agrees websites cause small children's small attention span
B.Jane Healy believes computer games can do good to children's reasoning
C.Susan Greenfield's warnings have been brought to wide public attention
D.Sue Palmer's book Toxic Childhood discusses the development of networking
4..
What is the purpose of this passage?
A.To tell us the conflict between neuroscientists and psychologists on websites.
B.To present some negative opinions on social networking websites.
C.To offer advice on the problem of brain damage caused by social networking.
D.To analyse how social networking websites cause damage in the brains of teenagers.
高二英语阅读理解简单题查看答案及解析
MySpace, the social networking website, is different from other websites which only provide stories about other people. MySpace is a place that allows you to broadcast your own stories and personal information to as many people as you like. Started two years ago, it is a big source of information for and about American kids.
Teenagers and their parents feel very differently about it. Teens are rushing to join the site, not sharing their parents' worries. It signals yet another generation gap in the digital era.(数字时代)
For teenagers, it is reliable network to keep in touch with their friends. They will often list their surnames, birthdays, afterschool jobs, school clubs, hobbies and other personal information.
“MySpace is an easy way to reach just about everyone. I don't have all the phone numbers of all my acquaintances (熟人). But if I want to get in touch with one of them, I could just leave them a message on MySpace.” said Abby Van Wassen. She is a sixteen year old student at Woodland Hills High of Pittsburgh, Pennsylvania.
Parents on the other hand are seriously concerned about the security problems of MySpace.
“Every time we hold a parents meeting, the first question is always about MySpace,” said Kent Gates, who travels the country doing Internet safety seminars (研讨会).The National Center for Missing and Exploited Children has received at least 288 MySpace related complaints, according to Mary Beth Buchanan, a lawyer in Pittsburgh.
“Your profile on MySpace shows all your personal information to anyone on the Web. And MySpace even lists this information by birthplace and age. It's like a free checklist(清单)for troublemakers and it endangers children,” Buchanan said.
1.From the passage we can learn that MySpace ________.
A.brings about the generation gap
B.is very careful about people's privacy
C.encourages you to list your personal information
D.lists the telephone numbers of your friends
2.Why are some parents against MySpace?
A.Because MySpace has a bad influence on their children.
B.Because they don't want to pay so much money for MySpace.
C.Because it takes up too much of their children's spare time.
D.Because troublemakers can easily approach their children through the site.
3.The writer's attitude towards MySpace is ________.
A.negative B.positive C.optimistic D.objective
4.Which of the following can be the best title of the passage?
A.Internet safety B.MySpace C.Generation gap D.The digital era
高二英语阅读理解中等难度题查看答案及解析
Social networking sites like Facebook and Twitter have changed the way that people interact and connect on a daily basis. They are changing the face of relationships of every kind. One of the major concerns that have caught the attention of many, is the influence that social media may be having on social anxiety disorders.
If removed from their phone for a few hours or a few days, the average person would likely feel anxious about not being “connected”. Most people have probably experienced an occasion in which they posted a creative photo, and waited to see “how many” or “retweets” they received. If this number is lower than expected, the(自我)ego is going to take a hit. There is also constant checking of the number of “followers” and “friends” that you have, and these numbers can have a direct influence on feelings of acceptance and popularity.
Anxiety can arise from feeling at a loss when faced with too much going on at one time Multitasking can very quickly lead to increased levels of anxiety. Most people can likely relate to feeling the constant need to check their phone while driving, during meals or at work. This desire is actually leading to increased levels of anxiety. The choice to be constantly connected leads to the feeling of having to always make yourself available.
Social anxiety is much different from the anxiety one feels from being offline. It’s a more serious type of anxiety resulting from the fear of being judged by others while in a social interaction. Cases can range from mild--- and are often the cause of a lot of drinking with others to severe, in which case a person may avoid parties and get-togethers altogether.
The degree to which social media and technology are changing our lives and introducing new forms of anxiety is anything but deniable(可否认的). The real question is to what extent are they introducing new disorders or increasing existing ones like social anxiety. It’s certainly a topic worth studying more to determine who is being helped, who is being harmed and how social anxiety can be dealt with.
1.What is the major focus of the text?
A.Human desire for social interaction.
B.The influence of social media on anxiety.
C.Anxiety resulting from interpersonal relationships.
D.The popularity of social media in people’s daily life.
2.How does the author explain social anxiety in Paragraph 2?
A.By giving examples. B.By offering statistics.
C.By providing processes. D.By making comparisons.
3.According to the author, which of the following can lead to increased levels of anxiety?
A.Not being available for get-togethers. B.Chatting on the phone with a friend.
C.Using the phone while driving. D.Eating meals alone.
4.What does the underlined word “they” in the last paragraph refer to?
A.Life changes. B.Anxiety degrees.
C.New forms of anxiety. D.Social media and technology.
高二英语阅读理解困难题查看答案及解析
The small number of newborn babies, which has been caused by high prices and the changing social situation of women, is one of the most serious problems in Asia. When people talk about it, you can hear a word invented in Japan, “DINKS”, which means Double Income No Kids.
In many major Asian cities like Seoul, Singapore, and Tokyo, the cost of a house is extremely high. A young couple who want to buy their own house may have to pay about $3000,000 (though prices have fallen). For a flat with one bedroom, one dining-room, a kitchen, and a bathroom, the couple will pay about $900 a month. What’s more, if they want to have a child, the child’s education is very expensive. For example, most kindergarten charges are at least $5,000 a year. In such a situation, it’s difficult to afford children.
The number of married women who want to continue working increases rapidly because they enjoy their jobs. However, if they want to have children, they immediately have serious problems. Though most companies allow women to leave their jobs for a short time to have a baby, they expect women with babies to give up their jobs. In short, if they want to bring up children properly, both parents have to work, but it is hard for mothers to work. Indeed, women who want to continue working have to choose between having children or keeping their jobs.
In a word, Asian governments must take steps to improve the present situation as soon as possible.
1. What is the main problem being discussed in the passage?
A. The small number of newborn babies.
B. The changing social situation of women.
C. The high prices of houses and education.
D. The necessary steps of Asian government.
2.According to the passage, which of the following is true?
A. It is easy for a couple to afford a child in Asia.
B. The prices of houses in Asia are quite low now.
C. Fewer and fewer married women want to have a job.
D. The word “DINKS” appeared in an Asian country.
3.To buy a flat and send a child to kindergarten, how much will a couple pay each year?
A. $5,000. B. $5,900.
C. $10,800. D. $15,800.
4. The writer seems to believe that Asian governments should ________.
A. let women stay at home and have a baby
B. allow only one of the parents to go out to work
C. care for the growing needs of women for jobs
D. punish the companies that permit women to leave
高二英语阅读理解中等难度题查看答案及解析
Rising levels of carbon dioxide in the atmosphere are a major cause of climate change, and now a new study has confirmed that atmospheric CO2 is also affecting the ocean chemistry and potentially harming sea life.
Montana State University scientist Robert Dore has been researching the water in the Pacific Ocean for almost two decades. “We've been going to the same spot in the Pacific Ocean, and we try and characterize longterm change in the open ocean environment. And one of the key things that we measure is CO2 levels. And we've been able to record this increasing quantity of atmospheric CO2 into the ocean.”
Scientists expected that as atmospheric CO2 increased, more and more of the carbon dioxide would be absorbed into the ocean, affecting the chemical balance of the sea water, with a potentially harmful impact on shellfish and coral in particular.
“As carbon dioxide dissolves in the water, or seawater in this case, it forms a weak acid, carbonic acid,” Dore explains. “And therefore, as the concentration of CO2 in the atmosphere goes up and that exchanges with the surface seawater, it drives the PH down, and makes it more acidic.”
The seawater samples Dore and his colleagues have analyzed confirm what the theory predicts.
The effect was particular striking at about 250 meters down, and again at 500 meters. Dore and his colleagues came up with two possible explanations. It could be that surface water picked up CO2 and then moved to those depths. Or there could be a biological explanation.
“It's important to realize that the oceans are really becoming acidic. And it can have negative impacts on a whole variety of sea life from fish to coral. It's potentially catastrophic.”
1.What can be the best title of the passage?
A.Climate Change Affecting Seawater
B.Oceans Becoming More Acidic
C.Sea Life Facing Danger
D.Scientist Researching Seawater
2.With the increase of atmospheric CO2,________.
A.the surface water is becoming warmer
B.more corals will appear in the sea
C.the PH of the ocean out here has been increasing
D.the chemical balance of the seawater is affected
3.Which of the following shows the process of the impact of atmospheric CO2 on sea life?
a.Sea life is endangered.
b.CO2 goes into the surface water.
c.The ocean chemistry is affected.
d.CO2 decreases the PH and makes the seawater more acidic.
e. CO2 levels in the atmosphere go up.
A.a→e→b→c→d B.e→d→c→b→a
C.e→b→c→d→a D.a→b→c→d→e
高二英语阅读理解中等难度题查看答案及解析
Rising levels of carbon dioxide in the atmosphere are a major cause of climate change, and now a new study has confirmed that atmosphere CO2 is also affecting the ocean chemistry and potentially harming sea life.
Montana State University scientist Robert Dore has been researching the water in the Pacific Ocean for almost two decades. “We’ve been going to the same spot in the Pacific Ocean, and we try and characterize long-term change in the open ocean environment. And one of the key things that we measure is CO2 levels. And we’ve been able to record this increasing quantity of atmosphere CO2 into the ocean.”
Scientists expected that as atmosphere CO2 increased, more and more of the carbon dioxide would be absorbed into the ocean, affecting the chemical balance of the sea water, with a potentially harmful impact on shellfish and coral in particular.
“As carbon dioxide dissolves in the water or seawater in this case, it forms a weak acid, carbonic acid,” Dore explains. “And therefore, as the concentration of CO2 in the atmosphere goes up and that exchanges with the surface seawater, it drives the pH down, and makes it more acidic.”
The seawater samples Dore and his colleagues have analyzed confirm what the theory predicts.
The effect was particular striking at about 250 meters down, and again at 500 meters. Dore and his colleagues came up with two possible explanations. It could be that surface water picked up CO2 and then moved to those depths. Or there could be a biological explanation.
“It’s important to realize that the oceans are really becoming acidic. And it can have negative impacts on a whole variety of sea life from fish to coral. It’s potentially catastrophic.”
1.What can be the best title of the passage?
A. Scientist Researching Seawater
B. Sea Life Facing Danger
C. Oceans Becoming More Acidic
D. Climate Change Affecting Seawater
2.With the increase of atmospheric CO2, _______.
A. more corals will appear in the sea
B. the chemical balance of the seawater is affected
C. the surface water is becoming warmer
D. the pH of the ocean out here has been increasing
3.Which of the following shows the process of the impact of atmospheric CO2 on sea life?
a. Sea life is endangered.
b. CO2 goes into the surface water.
c. The ocean chemistry is affected.
d. CO2 decreases the pH and makes the seawater more acidic.
e. CO2 levels in the atmosphere go up.
A. a→b→c→d→e B. e→b→c→d→a
C. a→e→b→c→d D. e→d→c→b→a
4.Scientist Robert Dore came to the conclusion based on_______.
A. the expectation of other scientists
B. some former theory
C. his research and analysis
D. a major cause of climate change
高二英语阅读理解中等难度题查看答案及解析
Social media can be a convenient way to extend your network, staying in touch with your grandma, or sharing photos of your new puppy. Nevertheless, social media can be temible for your health. It’s our use of it that’s out of control.
British anthropologist and evolutionary psychologist Robin Dunbar developed the idea that 150 people is the maximum number of meaningful connections anyone can have. You may have 800 friends on Wechat, but we’re not connecting with them in person. Your QQ connections may be vast, but how many of them do you have meaningful interactions with?
If you’re using social media to feel more connected, a recent study published in the American Joumal of Health Promotion suggests that it’s not working, and it an also contribute to unfavorable connections and even depression. Positive interactions on social media don’t help people feel happier. Negative interactions, on the other hand, bring more feelings of sadness. The same goes for comparison, which social media encourages. Another study, published by the American Psychological Association, shows comparing yourself to others via social media also has negative effects, leading to symptoms of depression.
Reaching for your cell phone as a mental break is also a bad idea. Research by Rutgers University compared participants in the midst of completing a task who took a break with their cell phones, with paper and pencils, and who took no break at all. Those who used their cell phones during their break solved 22% fewer problems and took 19% longer to complete their tasks than those under the other two conditions.
So how should you manage your social media usage?
First, know your time and purposes of use. Use the tracking function on your device to find out how much you’re using it and what you’re using it for. After this, get away from your device unless you have to use it. As tough as it might be, turn off and tune into the world around you.
Then, be in charge of your device, rather than let it be in charge of you. Your phone s rings or vibrations don’t mean you must respond to them. Remind yourself that you’re in charge, not your device or the people on the other end of it who’ve just contacted you.
Finally, consider using your device as a relationship builder. Use your apps to find your friends and make your dinner reservation so you can catch up face-to-face your favorite restaurant, where you’ll keep your phone out of sight.
When you’re in control of your digital consumption, social media becomes a tool to enrich your life and not a distraction (分心) that makes you feel miserable.
1.The author might agree that ________.
A.social media is immediate and interactive
B.it is hard to live without digital devices
C.friends on QQ are not friends indeed
D.improper social media use is harmful
2.American Journal of Health Promotion suggests that using social media ________.
A.can’t promote your expected connections
B.breaks up the meaningful communication
C.causes the unnecessary comparison
D.can’t bring more positive interactions
3.From the research by Rutgers University, we might conclude that ________.
A.participants without cell phones had quicker and deeper thinking
B.using cell phones couldn’t give participants mental breaks
C.cell phone users couldn’t complete their task successfully
D.mental breaks reduce efficiency of solving problems
4.To use social media as a relationship builder, you can ________.
A.call your friends to play online games together
B.book movie tickets for family time through apps
C.look through WeiBo when you have a family reunion
D.reply messages on We Chat while having dinner with friends
5.What would be the best title for the passage?
A.Is social media killing your health?
B.How does social media affect your life?
C.Social media: to be or not to be?
D.Social media: use it wisely!
高二英语阅读理解中等难度题查看答案及解析
Teens For Planet Earth
This is a social networking site for teenagers who want to get involved in protecting our planet. They can connect with other green-minded teens, choose a project or create their own. Teens For Planet Earth encourages young folks to get busy in their own communities. They offer guidance on local projects with categories such as habitats, animals, water and education. Awards are given to active members.
Meez
At Meez, teens can create their own avatars(头像), rooms and virtual pets. It is a social community of creative people that combines avatars, virtual worlds and games. Meez offers contests and chat as well as homework help, a fashion central and a writers’ corner. A chat area for younger teens is available. Other areas are music, geek(极客)central, art and sports.
Cyberteens
Cyberteens is another cool site that celebrates the teen years. Here teenagers can find community, games, and news. There is a link called “creativity” where teens can share their poems, stories, photos and artwork. The “cool links” section offers a huge variety of options to the curious teens. This site also has surveys and helps with jobs and school work.
Student.com
Student.com is a resource site for teens and high school students. Its social network has over 900,000 members. Members earn points to win prizes just by browsing and they offer several multi-player games. Points are used to buy items at auction(拍卖会). Student.com is filled with useful information and articles.
1.What is Teens For Planet Earth aimed to?
A.Set up a project.
B.Give awards to teens.
C.Get young folks busy.
D.Give advice on local projects.
2.What makes Student.com special among these websites?
A.It has the most members.
B.Teens can read articles on it.
C.It offers help on school work.
D.Teens can make purchases on it.
3.What can we infer about the websites mentioned in the text?
A.They provide game platforms.
B.They benefit teens in their social life.
C.They award outstanding teens.
D.They offer various study guidance.
高二英语阅读理解中等难度题查看答案及解析
Facebook is an Internet-based social network site that lets people get in touch with family and friends and reach out to people with common interests around the world, all through computer. It is very popular, with more than 900 million users. If Facebook were a country, it would have about three times the population of the United States.
Documents filed with US. financial regulators say Facebook has hundreds of millions of active users who send billions of messages each day and upload 250 million photographs on their personal pages. Facebook users have registered 100 billion “friends.”
On Facebook, “Friending” someone means you add the person to your list of people you can communicate with directly, which often allows the person to see more information about you than you share with the general public.
Facebook was started by Mark Zuckerberg and other students at Harvard University in 2004, and has grown at an amazingly fast pace.
Facebook makes money when advertisers pay to get access to hundreds of millions of Facebook users. Advertisers can often direct their messages to the people most interested in their products because Facebook computers keep track of information that users place on their pages. For example, a person interested in diving, planning a wedding, looking for work, or suffering from diabetes(糖尿病) may see advertisements related to those topics.
Facebook has become so much a part of the culture of the United States and other nations that it has been the subject of a Hollywood movie. It is a key marketing tool for many businesses, and its users’ content has been used as evidence in some divorce or criminal cases.
1.From the first paragraph, we can learn that ________.
A. about 900 million Americans are using Facebook
B. Facebook is widely used in the world
C. Facebook is a country in the Internet
D. Facebook is a place where people can meet face to face
2.If you are a friend of someone on Facebook, you__________ .
A. will have 100 billion friends
B. can download 250 million photographs
C. will share more private information
D. have to send message every day
3.Advertisers use Facebook because they can know__________.
A. who are interested in their products
B. how to keep track of information
C. what products are popular with the young
D. where their products are sold well
4.What might be the most suitable title for the passage?
A. Who starts Facebook?
B. How to use Facebook?
C. When is Facebook on?
D. What is Facebook?
高二英语阅读理解中等难度题查看答案及解析
Long-time exposure to air pollution can lead to physical changes in the brain and cause trouble in learning and memory, and even anxiety. This is suggested by the results of new research on mice.
While other studies have shown the harmful effects of polluted air in the lungs and heart, this is the first to show the negative effect on the brain.
The team of Laura Fonken, Randy Nelson, from the Ohio State University, USA, has spread to the brain a previous line of research which found that fine particulate (微粒) matter floating in the air mainly because of air pollution caused by humans, causes swelling in much of the body, and may be related to high blood pressure problems, and some other diseases.
In the research Fonken and his colleagues exposed mice to polluted air for six hours each day, five days a week, over a period of 10 months, almost half the average life length of mice.
Polluted air contains fine particles created by cars, factories and natural dust. Fine particles of this kind are tiny, about 2.5 micrometers in diameter, or about one-thirtieth the width of a human hair. These particles can go deep into lungs and other organs.
The concentration of this particulate material to which they exposed mice is equal to the concentration at which people can be exposed in some polluted urban areas.
After a period of 10 months, the researchers got the animals to have a series of behavioral tests. Both the behavior of mice and the results of neurological(神经的) tests done to them show that those within the polluted air had more problems in learning and memory, and higher levels of anxiety.
The results suggest that long-time exposure to polluted air can have measurable negative effects on the human brain and can cause a variety of mental health problems. This could have important consequences for those living and working in polluted urban areas.
1.The results of new research on mice first suggest that polluted air mainly does harm to ________.
A. normal organs B. lungs and heart
C. mental health D. blood pressure
2.The bad effects of tiny particles in polluted air are those except ________.
A. high blood pressure problems
B. making human hair thinner
C. different kinds of diseases
D. swelling in much of the body
3.From the last sentence we can infer that people living in polluted urban areas ________.
A. are likely to suffer from mental problems
B. can measure the negative effect on them
C. show little concern for air pollution
D. can be exposed to polluted air longer
4.Which of the following is the best title for the passage?
A. Long-time Exposure to Air Pollution
B. Evidence and Concern of Air Pollution
C. Measurable Effect on Human Brain
D. Mental Problems Caused by Air Pollution
高二英语阅读理解中等难度题查看答案及解析