阅读下列短文，从每题所给的四个选项 （A 、B 、C 和 D ）中 ，选出最佳选项。
The sharing economy has grown in recent years to include everything from apartment sharing to car sharing to community tool sharing. Since 2009,a new form of sharing economy has been emerging in neighborhoods throughout the US and around the world—Little Free Libraries. The libraries are boxes placed in neighborhoods where residents(居民) can take out and leave books. Little Free Libraries come in all shapes and sizes. Some libraries also have themes, focusing on books for children, adults, or tour guides.
In 2009,Tod Bol built the first Little Free Library as a gift to his mother, a devoted reader. When he saw the people of his community gathering around it, exchanging conversations as well as books, he knew he wanted to take his simple idea further. “I think Little Free Libraries open the door to conversations we want to have with each other.” Bol said.
Since then, his idea has become a movement, spreading from state to state and country to country. According to Little Free Library. org, there are now 18,000 of the little structures around the world, located in each of the 50 US states and 70 countries in Europe, Africa and Asia.
The Internet has helped to spread Little Free Libraries. But an Atlantic article says the little structures serve as a cure for a world of e-reader downloads. The little wooden boxes are refreshingly physical and human. For many people, the sense of discovery is Little Free Libraries’ main appeal. “A girl walking home from school might pick up a graphic novel that gets her excited about reading; a man on his way to the bus stop might find a volume of poetry that changes his outlook on life,” says the Atlantic article. “Every book is a potential source of inspiration.”
1.How do Little Free Libraries get their books?
A. Citizens shared them. B. Tod Bol donated them.
C. US government provided them. D. The communities bought them.
2.Why did Tod Bol want to build more Little Free Libraries?
A. He wanted to promote his idea worldwide.
B. He was inspired by the sharing economy.
C. They can offer neighbors more chances to talk.
D. They are a gift to please his mother.
3.According to the Atlantic article , Little Free Libraries _________.
A. help cut down on e-reading
B. benefit the spread of the Internet
C. promote e-reader downloads
D. call on human to care about each other
4.Little Free Libraries attract readers most in that .
A. they connect strangers together
B. they are located all over the world
C. they are in various shapes and sizes
D. they may give readers a sense of discovery
高三英语阅读理解中等难度题
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。
The stories we share with one another are important． They show wisdom and provide inspiration． They are important to our development． But sometimes people choose not to tell.
Consider the negative effects of not sharing a story in the news: People are wondering if public health officials are holding back too much information about the recent outbreak of Ebola.
There is a danger in holding back stories that ought to be told． Bobette Buster said it like this, “The fact is, history has shown us that stories not told can become like a dangerous genie (妖怪) left in a bottle． When they are finally uncorked, their power to destroy is set free.”
There are a number of reasons why we hide parts of our story: they often show our weaknesses or expose our disadvantages; they require courage and strength to share; and of course, there are some stories that should be kept secret—especially those that embarrass someone else.
Most of us have two selves: the one we display on the outside and the one we actually are on the inside． And the better we get at hiding the stories that show our true selves, the more damage we may be causing to ourselves and to others.
Honesty and openness is important: It proves we are trustworthy． It displays we are human． We are not perfect or better．It highlights the importance of hard work and personal development． Hard work may not allow us to overcome our disadvantages completely． But with hard work, we do not have to be restricted to our mistakes.
Does this mean we admit every weakness, every disadvantage, and every secret regret to everybody we meet? No, of course not． There is a time and a place and a certain level of relationship necessary for some stories to be told in an appropriate manner.
1.What’s the function of the example in Paragraph 2?
A． It reflects that people are concerning about the spread of Ebola.
B． It shows the bad effect caused by sharing a story.
C． It proves not sharing a story can cause trouble.
D． It concludes that one should share a story at a proper time.
2.One of the reasons why people are unwilling to share experiences is that _______.
A． story-sharing highlights the importance of hard work
B． people are used to exposing their weaknesses
C． people sometimes have no courage to share their stories
D． some stories make themselves feel uneasy
3.Which is close in meaning to the underlined word “uncorked” in Paragraph 3?
A． freed B． broken C． unfolded D． untouched
4.The writer aims to convince us to _______.
A． be open to people close to you by sharing some secrets
B． share stories appropriately for the good of others and ourselves
C． remove the dangers that can be caused by untold stories
D． realize the importance of being honest when making friends
高三英语阅读理解中等难度题查看答案及解析
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。
The stories we share with one another are important． They show wisdom and provide inspiration． They are important to our development． But sometimes people choose not to tell.
Consider the negative effects of not sharing a story in the news: People are wondering if public health officials are holding back too much information about the recent outbreak of Ebola.
There is a danger in holding back stories that ought to be told． Bobette Buster said it like this, “The fact is, history has shown us that stories not told can become like a dangerous genie (妖怪) left in a bottle．When they are finally uncorked, their power to destroy is set free.”
There are a number of reasons why we hide parts of our story: they often show our weaknesses or expose our disadvantages; they require courage and strength to share; and of course, there are some stories that should be kept secret—especially those that embarrass someone else.
Most of us have two selves: the one we display on the outside and the one we actually are on the inside． And the better we get at hiding the stories that show our true selves, the more damage we may be causing to ourselves and to others.
Honesty and openness is important: It proves we are trustworthy． It displays we are human． We are not perfect or better． It highlights the importance of hard work and personal development． Hard work may not allow us to overcome our disadvantages completely． But with hard work, we do not have to be restricted to our mistakes.
Does this mean we admit every weakness, every disadvantage, and every secret regret to everybody we meet? No, of course not．There is a time and a place and a certain level of relationship necessary for some stories to be told in an appropriate manner.
1.What’s the function of the example in Paragraph 2?
A． It reflects that people are concerning about the spread of Ebola.
B． It shows the bad effect caused by sharing a story.
C． It proves not sharing a story can cause trouble.
D． It concludes that one should share a story at a proper time.
2.One of the reasons why people are unwilling to share experiences is that _______.
A． story-sharing highlights the importance of hard work
B． people are used to exposing their weaknesses
C． people sometimes have no courage to share their stories
D． some stories make themselves feel uneasy
3.Which is close in meaning to the underlined word “uncorked” in Paragraph 3?
A． freed B． broken C． unfolded D． untouched
4.The writer aims to convince us to _______.
A． be open to people close to you by sharing some secrets
B． share stories appropriately for the good of others and ourselves
C． remove the dangers that can be caused by untold stories
D． realize the importance of being honest when making friends
高三英语阅读理解简单题查看答案及解析
阅读下列短文，从每题所给的四个选项 （A 、B 、C 和 D ）中 ，选出最佳选项。
The sharing economy has grown in recent years to include everything from apartment sharing to car sharing to community tool sharing. Since 2009,a new form of sharing economy has been emerging in neighborhoods throughout the US and around the world—Little Free Libraries. The libraries are boxes placed in neighborhoods where residents(居民) can take out and leave books. Little Free Libraries come in all shapes and sizes. Some libraries also have themes, focusing on books for children, adults, or tour guides.
In 2009,Tod Bol built the first Little Free Library as a gift to his mother, a devoted reader. When he saw the people of his community gathering around it, exchanging conversations as well as books, he knew he wanted to take his simple idea further. “I think Little Free Libraries open the door to conversations we want to have with each other.” Bol said.
Since then, his idea has become a movement, spreading from state to state and country to country. According to Little Free Library. org, there are now 18,000 of the little structures around the world, located in each of the 50 US states and 70 countries in Europe, Africa and Asia.
The Internet has helped to spread Little Free Libraries. But an Atlantic article says the little structures serve as a cure for a world of e-reader downloads. The little wooden boxes are refreshingly physical and human. For many people, the sense of discovery is Little Free Libraries’ main appeal. “A girl walking home from school might pick up a graphic novel that gets her excited about reading; a man on his way to the bus stop might find a volume of poetry that changes his outlook on life,” says the Atlantic article. “Every book is a potential source of inspiration.”
1.How do Little Free Libraries get their books?
A. Citizens shared them. B. Tod Bol donated them.
C. US government provided them. D. The communities bought them.
2.Why did Tod Bol want to build more Little Free Libraries?
A. He wanted to promote his idea worldwide.
B. He was inspired by the sharing economy.
C. They can offer neighbors more chances to talk.
D. They are a gift to please his mother.
3.According to the Atlantic article , Little Free Libraries _________.
A. help cut down on e-reading
B. benefit the spread of the Internet
C. promote e-reader downloads
D. call on human to care about each other
4.Little Free Libraries attract readers most in that .
A. they connect strangers together
B. they are located all over the world
C. they are in various shapes and sizes
D. they may give readers a sense of discovery
高三英语阅读理解中等难度题查看答案及解析
阅读下面短文，从短文后各题的A、B、C、D四个选项中，选出适合填入对应空白处的最佳选项。并在答题卡上将该选项涂黑。
I arrived in the classroom, ready to share my knowledge and experience with 75 students who would be my English Literature class．Having taught in 1for 17 years, I had no 2about my ability to hold their attention and to 3on them my admiration for the literature of my mother tongue．
I was shocked when the monitor shouted, “4!”
The entire class rose as I entered the room, and I was somewhat 5about how to get them to sit down again, but once that awkwardness was over, I quickly 6my calmness and began what I thought was a fact-packed lecture, sure to gain their respect --- perhaps 7their admiration．I went back to my office with the rosy glow which comes from a sense of achievement．
My students 8diaries．However, as I read them, the rosy glow was gradually 9by a strong sense of sadness．The first diary said, “Our literature teacher didn’t teach us anything today． 10her next lecture will be better．” Greatly surprised, I read diary after diary, each expressing a 11theme．“Didn’t I teach them anything? I described the entire philosophical framework of Western thought and laid the historical 12for all the works we will study in class,” I complained．“How 13they say I didn’t teach them anything?”
It was a long term, and it 14became clear that my ideas about education were not the same as 15of my students．I thought a teacher’s job was to raise 16questions and provide enough background so that students could 17their own conclusions．My students thought a teacher’s job was to provide 18information as directly and clearly as possible．What a difference!
19, I also learned a lot, and my experience with my Chinese students has made me a 20American teacher, knowing how to teach in a different culture．
1.A．the UK B．the US C．China D．Australia
2.A．worry B．idea C．doubt D．experience
3.A．impress B．put C．leave D．fix
4.A．Attention B．Look out C．At ease D．Stand up
5.A．puzzled B．sure C．depressed D．worried
6.A．found B．returned C．regained D．followed
7.A．more B．even C．yet D．still
8.A．passed B．borrowed C．kept D．read
9.A．replaced B．taken C．caught D．moved
10.A．Naturally B．Perhaps C．Fortunately D．Reasonably
11.A．different B．strong C．similar D．usual
12.A．happenings B．characters C．development D．background
13.A．should B．need C．will D．must
14.A．immediately B．certainly C．simply D．gradually
15.A．that B．what C．those D．ones
16.A．difficult B．interesting C．ordinary D．unusual
17.A．draw B．get C．decide D．give
18.A．strange B．standard C．exact D．serious
19.A．Therefore B．However C．But D．Though
20.A．normal B．happy C．good D．better
高三英语完形填空中等难度题查看答案及解析
阅读下面短文，从短文后各题所给的四个选项(A、B、C和D)中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
Life is like potato salad; when it’s shared it becomes a picnic.
When my three children were young, my husband, Roy, and I were very 1..
“Can we go on a picnic, Mom?” my six-year-old daughter, Becky 2. . “Please.”
I had said no so many times in the 3. months, and I decided the usual Saturday morning chores (日常工作) could wait. To her 4., I agreed.
I prepared a few sandwiches and 5. a cooler with ice and drinks and called Roy
6.. My eleven-year-old twin sons put the cooler and the picnic basket in the trunk and off we went to spend some 7. time together as a family.
About the time I got the lunch 8. out on the table, Roy arrived on the 9..
That was one of the happiest meals we ever shared together. The meal was filled with
10.. We felt a closeness that had been hidden by work and school 11. for so many months. Roy and the boys 12. rocks into the lake. Becky fed the ducks and I sat quietly on the picnic table, 13. God for blessing me with such a wonderful family.
That night as our 14. went to bed, I kissed their cheeks and realized what a wonderful life I had.
As I walked out of the room it dawned on me that even the busiest 15. could become a picnic when it’s shared with the ones you 16..
Even though the kids have now grown up and 17. from home, I can still remember how I felt that day while sitting at the picnic table.
Maybe today would be a good time to 18. potato salad, call all of my grown kids, feed some hungry 19. and skipped a few rocks into the lake. Since life is like potato salad, let’s make it a 20..
21.A. old B. poor C. busy D. miserable
22.A. begged B. asked C. doubted D. wondered
23.A. coming B. recent C. following D. later
24.A. doubt B. disappointment C. sadness D. surprise
25.A. supplied B. provided C. combined D. filled
26.A. off work B. at home C. at work D. on business
27.A. unhappy B. quality C. quantity D. sad
28.A. spread B. taken C. made D. cooked
29.A. scene B. view C. event D. landscape
30.A. sadness B. expectation C. hope D. laughter
31.A. orders B. charges C. activity D. responsibilities
32.A. missed B. took C. skipped D. left
33.A. praying B. praising C. thanking D. trusting
34.A. family B. children C. friends D. parents
35.A. lifestyle B. time C. world D. family
36.A. enjoy B. own C. have D. love
37.A. left alone B. passed away C. ran away D. moved away
38.A. supply B. cook C. watch D. plant
39.A. ducks B. children C. family D. people
40.A. salad B. life C. picnic D. hope
高三英语完形填空简单题查看答案及解析
阅读下面短文，掌握其大意，然后从36—55各题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
Teaching my first child, Danae, to share her toys was the biggest challenge. To 36 this, we started inviting other children to play, which could help Danae discover that it’s 37 to share with others – a lesson I needed to 38 myself as well, as it 39 .
One evening Danac had 40 a friend, Natalie, to play with her. Their favorite was a children’s 41 game called Go Fish. That evening, 42 Natalie left, Danae came to me and said, “Mommy, I’d like to give these to Natalie tomorrow. They’re her favorites.”
She help up three cards from the Go Fish game. I tried to 43 that I didn’t want her to give them away because then our 44 wouldn’t be complete. “But I really want her to have them!” Danae 45 . I thought perhaps she didn’t understand that when she gave something away, it was gone 46 . So I tried again, saying, “47 you give the cards to her, you can’t 48 them back tomorrow.”
A look of 49 came over Danae’s face. For a moment I was happy that she seemed to 50 . But then she smiled and said. “Well, that’s okay, I want her to have them anyway.”
What could I say to that? I sat 51 for a moment and then I realized I had been trying for so long to 52 her to share. Did it 53 that our Go Fish set would be 54 ? What mattered was that my daughter was learning the 55 of giving, that she was thinking about others instead of herself, and that she was trying to make her friends happy. Isn’t that what life is all about?
1.A．achieve B．apply C．receive D．get
2.A．kind B．gentle C．fun D．merciful
3.A．design B．know C．create D．review
4.A．turned up B．turned away C．turned to D．turned out
5.A．begged B．encouraged C．invited D．found
6.A．box B．card C．paper D．show
7.A．before B．while C．after D．until
8.A．explain B．suggest C．respond D．teach
9.A．thing B．card C．set D．toy
10.A．insisted B．recommended C．announced D．cried
11.A．surely B．suddenly C．forever D．indeed
12.A．If B．Once C．As D．Unless
13.A．ask for B．call for C．look for D．care of
14.A．surprise B．concern C．delight D．satisfaction
15.A．understand B．accept C．refuse D．doubt
16.A．sadly B．angrily C．quietly D．slowly
17.A．conduct B．ask C．force D．help
18.A．work B．mean C．remind D．matter
19.A．incomplete B．lost C．limited D．gone
20.A．content B．usefulness C．way D．joy
高三英语完型填空简单题查看答案及解析
阅读下面短文，掌握其大意，然后从各题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
Teaching my first child, Danae, to share her toys was the biggest challenge. To 1this, we started inviting other children to play, which could help Danae discover that it’s 2to share with others – a lesson I needed to 3myself as well, as it 4.
One evening Danac had 5a friend, Natalie, to play with her. Their favorite was a children’s 6game called Go Fish. That evening, 7Natalie left, Danae came to me and said, “Mommy, I’d like to give these to Natalie tomorrow. They’re her favorites.”
She help up three cards from the Go Fish game. I tried to 8that I didn’t want her to give them away because then our 9wouldn’t be complete. “But I really want her to have them!” Danae 10. I thought perhaps she didn’t understand that when she gave something away, it was gone 11. So I tried again, saying, “12you give the cards to her, you can’t 13them back tomorrow.”
A look of 14came over Danae’s face. For a moment I was happy that she seemed to 15. But then she smiled and said. “Well, that’s okay, I want her to have them anyway.”
What could I say to that? I sat 16for a moment and then I realized I had been trying for so long to 17her to share. Did it 18that our Go Fish set would be 19? What mattered was that my daughter was learning the 20of giving, that she was thinking about others instead of herself, and that she was trying to make her friends happy. Isn’t that what life is all about?
1.A．achieve B．apply C．receive D．get
2.A．kind B．gentle C．fun D．merciful
3.A．design B．know C．create D．review
4.A．turned up B．turned away C．turned to D．turned out
5.A．begged B．encouraged C．invited D．found
6.A．box B．card C．paper D．show
7.A．before B．while C．after D．until
8.A．explain B．suggest C．respond D．teach
9.A．thing B．card C．set D．toy
10.A．insisted B．recommended C．announced D．cried
11.A．surely B．suddenly C．forever D．indeed
12.A．If B．Once C．As D．Unless
13.A．ask for B．call for C．look for D．care for
14.A．surprise B．concern C．delight D．satisfaction
15.A．understand B．accept C．refuse D．doubt
16.A．sadly B．angrily C．quietly D．slowly
17.A．conduct B．ask C．force D．help
18.A．work B．mean C．remind D．matter
19.A．incomplete B．lost C．limited D．gone
20.A．content B．usefulness C．way D．joy
高三英语完形填空中等难度题查看答案及解析
阅读下面短文，掌握其大意，然后从各题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
Teaching my first child, Danae, to share her toys was the biggest challenge. To 1this, we started inviting other children to play, which could help Danae discover that it’s 2to share with others – a lesson I needed to 3myself as well, as it 4.
One evening Danac had 5a friend, Natalie, to play with her. Their favorite was a children’s 6game called Go Fish. That evening, 7Natalie left, Danae came to me and said, “Mommy, I’d like to give these to Natalie tomorrow. They’re her favorites.”
She help up three cards from the Go Fish game. I tried to 8that I didn’t want her to give them away because then our 9wouldn’t be complete. “But I really want her to have them!” Danae 10. I thought perhaps she didn’t understand that when she gave something away, it was gone 11. So I tried again, saying, “12you give the cards to her, you can’t 13them back tomorrow.”
A look of 14came over Danae’s face. For a moment I was happy that she seemed to 15. But then she smiled and said. “Well, that’s okay, I want her to have them anyway.”
What could I say to that? I sat 16for a moment and then I realized I had been trying for so long to 17her to share. Did it 18that our Go Fish set would be 19? What mattered was that my daughter was learning the 20of giving, that she was thinking about others instead of herself, and that she was trying to make her friends happy. Isn’t that what life is all about?
1.A．achieve B．apply C．receive D．get
2.A．kind B．gentle C．fun D．merciful
3.A．design B．know C．create D．review
4.A．turned up B．turned away C．turned to D．turned out
5.A．begged B．encouraged C．invited D．found
6.A．box B．card C．paper D．show
7.A．before B．while C．after D．until
8.A．explain B．suggest C．respond D．teach
9.A．thing B．card C．set D．toy
10.A．insisted B．recommended C．announced D．cried
11.A．surely B．suddenly C．forever D．indeed
12.A．If B．Once C．As D．Unless
13.A．ask for B．call for C．look for D．care of
14.A．surprise B．concern C．delight D．satisfaction
15.A．understand B．accept C．refuse D．doubt
16.A．sadly B．angrily C．quietly D．slowly
17.A．conduct B．ask C．force D．help
18.A．work B．mean C．remind D．matter
19.A．incomplete B．lost C．limited D．gone
20.A．content B．usefulness C．way D．joy
高三英语完形填空中等难度题查看答案及解析
阅读下面短文，掌握其大意．然后从1—15各题所给的A、B、C和D项中，选出最佳选项，并在答题卡上将该项涂黑。
Teaching my first child, Danae, to share her toys was the biggest challenge. To 1this, we started inviting other children to play, which could help Danae discover that it’s fun to share with others — a lesson I needed to 2myself as well, as it 3.
One evening Danae had 4a friend, Natalie, to play with her. Their favorite was a children’s card game called Go Fish. That evening, after Natalie left, Danae came to me and said, “Mommy, I’d like to give these to Natalie tomorrow. They’re her favorites.”
She held up three cards from the Go Fish game. I tried to 5that I didn’t want her to give them away because then our 6wouldn’t be complete. “But I really want her to have them!” Danae 7. I thought perhaps she didn’t understand that when she gave something away, it was gone 8. So I tried again, saying, “Once you give the cards to her, you can’t 9them back tomorrow.”
A look of 10came over Danae’s face. For a moment I was happy that she seemed to 11. But then she smiled and said. “Well, that’s okay; I want her to have them anyway.”
What could I say to that? I sat 12for a moment and then I realized I had been trying for so long to ask her to share. Did it 13that our Go Fish set would be 14? What mattered was that my daughter was learning the 15of giving, that she was thinking about others instead of herself, and that she was trying to make her friends happy. Isn’t that what life is all about?
1.A．achieve B．apply C．receive D．get
2.A．design B．know C．create D．review
3.A．turned up B．turned away C．turned to D．turned out
4.A．begged B．encouraged C．invited D．found
5.A．explain B．suggest C．respond D．teach
6.A．thing B．card C．set D．toy
7.A．insisted B．recommended C．announced D．cried
8.A．surely B．suddenly C．forever D．indeed
9.A．ask for B．call for C．look for D．care of
10.A．surprise B．concern C．delight D．satisfaction
11.A．understand B．accept C．refuse D．doubt
12.A．sadly B．angrily C．quietly D．slowly
13.A．work B．mean C．remind D．matter
14.A．incomplete B．lost C．limited D．gone
15.A．content B．usefulness C．way D．joy
高三英语完形填空中等难度题查看答案及解析
阅读理解。阅读下列短文, 从给的四个选项 (A、B、C和D) 中, 选出最佳选项。
Now many young people are traveling around the world on their own，not because they have no one to travel with，but because they prefer to go alone.
Kristina Wegscheider from California first traveled alone when she was at college and believes that it is something everyone should do at least once in their life.“It opens up your mind to new things and pushes you out of your comfort zone.” Wegscheider has visited 46 countries covering all seven continents.
In foreign countries，with no one to help you read a map，look after you if you get ill，or lend you money if your wallet is stolen，it is challenging.This is what drives young people to travel alone.It is seen as character building and a chance to prove that they can make it on their own.
Chris Richardson decided to leave his sales job in Australia to go traveling last year.He set up a website，The Aussie Nomad，to document his adventures.He says he wished he had traveled alone earlier.“The people you meet，the places you visit，or the things you do，everything is up to you and it forces you to grow as a person，” said the 30yearold man.
Richardson describes traveling alone like “a shot in the arm”，which “makes you a more confident person that is ready to deal with anything”．He said，“The feeling of having conquered something on my own is a major part of what drives me each day when I’m dealing with a difficult task.” “I walk around with my head up because I know deep down inside that nothing is impossible if you try.”
The great 19th century explorer John Muir once said，“Only by going alone in silence can one truly get into the heart of the wilderness.”
1.Which of the following will Kristina Wegscheider agree with?
A．Traveling alone is a necessary experience for everyone.
B．It is more meaningful to travel in foreign countries.
C．It is comfortable to travel around without a friend.
D．Traveling abroad helps people to find new things.
2.Traveling alone is challenging because________.
A．you have to make things on your own
B．it is hard for you to prove yourself to others
C．you can only depend on yourself whatever happens
D．it will finally build your character
3.What can we infer about Chris Richardson?
A．He started traveling alone at an early age.
B．He was once shot in the arm.
C．He used to work as a salesman.
D．His website inspires others a lot.
4.What is the best title for the passage?
A．Travel Abroad B．Travel Unaccompanied
C．Travel Light D．Travel Wide and Far
高三英语阅读理解困难题查看答案及解析