We all enjoy the colors of autumn leaves. Did you ever wonder how and why a fall leaf changes color? Where do the yellows and oranges come from? To answer those questions, we first have to understand what leaves are and what they do.
Leaves are nature's food factories. Plants take water from the ground through their roots. They take a gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into glucose, which is a kind of sugar. Plants use glucose as food for energy and as a building block for growing. The way plants turn water and carbon dioxide into sugar is called photosynthesis, which means " putting together with light. " A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is what gives plants their green color.
As summer ends and autumn comes, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter.
During winter, there is not enough light or water for photosynthesis. The trees will rest, and live off the food they stored during summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colors. Small a-mounts of these colors have been in the leaves all along. Covered up by the green chlorophyll, we just can't see them in summer.
The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves.
It is the combination of all these things that make the beautiful colors we enjoy in the fall.
小題1:The writer asked two questions in the beginning in order to        .
A.persuade readers to believe something
B.introduce the topic of the passage
C.get the readers excited
D.offer something to think over
小題2: Which of the following is True according to the passage?
A.Trees don't change colours with seasons.
B.Trees can still perform photosynthesis well in winter.
C.Trees have colours like yellow and orange even in summer.
D.Trees don't need food in winter.
小題3:Photosynthesis is a way that ___________________________.
A.plants change water and carbon dioxide into sugar
B.plants turn water and carbon dioxide into sugar with the help of sunlight
C.plants use glucose as food for energy and growing
D.chlorophyll is a great help
小題4: Which is the best title for this passage?
A.Colorful trees in autumnB.Mysteries of tree colors
C.Do you enjoy tree colors?D.Wonderful colors in autumn

小題1:B
小題2:C
小題3:B
小題4:B
練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目:高中英語(yǔ) 來(lái)源:不詳 題型:完形填空

Dear Seth,
You are only three years old, and at this point in your life you are not able to understand this letter. But some day when you___36___, I hope you will find something __37__in what I am going to share with you.
Life can be __38__ . There will be people in your life who won’t be very nice. They’ll __39___ you because you are different,  40 for no good reason . You will also face heartbreak and might be __41__ by those you love. I hope you don’t have to face these too much , but such things __42__.
Be open to life anyway. You’ll find cruelty(殘忍) and  43 in your journey through life , but don’t let that__44__   you from finding new things . Don’t retreat (退卻)from life , and don’t __45__ or wall yourself off . Be open to new things , new experiences ,and new people . You will __46__ many times ,but if you allow that to stop you from trying , you will __47_ many chances . Do remember failure is a stepping stone to __48__.
You will meet many people who will try to do __49__ than you , in school, in college, and at work. They’ll try to have nicer cars, bigger houses, nicer clothes, and so on. . To __50_ , life is a competition.However, I believe life is a __51_. If you always try your best to __52__ others, you are wasting your life . Learn to enjoy your life__53_ and you will make it a journey of __54__ ,of learning and of love.
Finally , know that I love you and always will. You are _55__ a really wonderful journey , and I will always be there for you.
Love
Dad
小題1:
A.grow upB.show upC. cheer upD.give up
小題2:
A.familiarB.valuableC.normalD.interesting
小題3:
A.unkindB.peacefulC.equalD.simple
小題4:
A.look atB.run afterC.laugh atD.look after
小題5:
A.ifB.butC.soD.or
小題6:
A.hurtB.foundC.a(chǎn)cceptedD.impressed
小題7:
A.matterB.workC.disappearD.happen
小題8:
A.luckB.painC.differenceD.hope
小題9:
A.protectB.encourageC.stopD.choose
小題10:
A.forgiveB.struggleC.competeD.hide
小題11:
A.leaveB.prepareC.escapeD.fail
小題12:
A.enjoyB.tryC.missD.meet
小題13:
A.successB.lifeC.a(chǎn)ctionD.sorrow
小題14:
A.earlierB.betterC.lessD.faster
小題15:
A.youB.meC.himD.them
小題16:
A.challengeB.dramaC.journeyD.dream
小題17:
A.changeB.pardonC.followD.beat
小題18:
A.somewhereB.insteadC.a(chǎn)fterwardsD.though
小題19:
A.crueltyB.dangerC.happinessD.quietness
小題20:
A.startingB.destroyingC.finishingD.replacing

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:完形填空

I ran into a stranger as he passed by. "I'm so  36 !" was my reply. Then he said, "Excuse me too. I wasn't even   37 you" .We were very polite, this stranger and I.
  38  at home, a different story is told---how we  39 our loved ones. While I was cooking ,my daughter came up to me quietly. When I   40 , I nearly knocked her down. "Get out of the way! "I barked She ran away, with her little heart broken. I didn't realize how  41 I'd spoken.
That night, as I lay  42 in bed, God's quiet voice spoke to me and said,  "While  43 with a stranger, you're calm and polite, but with those you love, you're quick to  44 . Go and look right now on the kitchen floor. You'll   45 some flowers there by the door. Those are the flowers she brought for you. She   46 them herself. She stood there _ 47 , not to spoil your surprise, and you never saw the tears in her eyes."   48 this time, I felt sad and my own tears had begun to   49 . "Are these the flowers you picked for me?" I asked. She   50, "I found them out by the tree. 1 knew you'd like them." I said, "I'm so sorry that I   51  them today. And I shouldn't have shouted at you that way." She whispered, “Mommy, that's okay... I still love you   52 .” I hugged her.
Are you aware that if you die tomorrow, the company that you are working for could easily  53  you in a matter of days? But the family you leave behind will feel the   54 for the rest of their lives. And come to think of it, we  55 more into our work than into our families –an unbalanced investment (投資) indeed.
小題1:A. angry
小題2:A. noticing
小題3:A. And
小題4:A. respect
小題5:A. cooked
小題6:A. aloud
小題7:A. asleep
小題8:A. dealing
小題9:A. quarrel
小題10:A. find
小題11:A. made
小題12:A. quickly
小題13:A. In
小題14:A. come
小題15:A. added
小題16:A. missed
小題17:A. forever
小題18:A. fire
小題19:A. loss
小題20:A. pass
B. sorry
B. knowing
B. So
B. regard
B. turned
B. clearly
B. still
B. meeting
B. excite
B. take
B. bought
B. eagerly
B. By
B. form
B. cried
B. lost
B. anyway
B. pay
B. trouble
B. lead 
C. sad
C. following
C. As
C. treat
C. began
C. difficultly
C. awake
C. talking
C. shout
C. enjoy
C. prepared
C. quietly
C. For
C. fall
C. smiled
C. destroyed
C. however
C. remember
C. problem
C. run
D. unlucky
D. understanding
D. But
D. show
D. worked
D. cruelly
D. upset
D. traveling
D. mistake
D. need
D. picked
D. nervously
D. After
D. flow
D. agreed
D. forgot
D. therefore
D. replace
D. care
D. pour
                   

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:完形填空

My grandparents were married for over half a century, and played their own special game from the time they had met each other. The goal of their game was to write the word "shmily" in a     31    place for the other to find. They took turns leaving "shmily" around the house, and as soon as one of them     32    it, it was their turn to hide it once more.
There was no     33    to the places where "shmily" would appear. Sometimes, "Shmily" was written in the     34    left on the mirror after a hot shower, where it would reappear bath after bath.     35   , my grandmother even unrolled an entire roll of toilet paper to     36    "shmily" on the very last sheet.
It took me a long time before I was able to fully     37    my grandparents' game. It was     38    their funny little game; it was a way of life. Grandma and Grandpa held hands every chance they could. They    39    kisses as they ran into each other in their tiny kitchen. Before every meal they bowed their heads and gave their     40   : a wonderful family, good fortune, and     41  .
But there was a    42   cloud in my grandparents' life: my grandmother had breast cancer, which had first appeared ten years earlier. As always, Grandpa was with her every
    43    of the way. He comforted her in their yellow room, painted that way     44____    she could always be surrounded by sunshine, even when she was too     45    to go outside.   Then one day, what we all     46    finally happened. Grandma was gone.
"Shmily." It was written in yellow on the pink ribbons of my grandmother's funeral bouquet. As the crowd     47    and the last mourners (哀悼者) turned to leave, my aunts, uncles, cousins and other family members     48    and gathered around Grandma     49   . Grandpa stepped up to my grand-mother's casket and,     50    with sorrow, he began to sing to her. Through his tears and grief, the song came, a deep and throaty lullaby (搖籃曲).
SHMILY: See how much I love you.
小題1:
A.exact
B.surprising
C.usual
D.regular
小題2:
A.discovered
B.defeated
C.folded
D.a(chǎn)nnounced
小題3:
A.start
B.point
C.doubt
D.end
小題4:
A.steam
B.water
C.a(chǎn)ir
D.dust
小題5:
A.In an instant
B.As a result
C.At one point
D.Once for all
小題6:
A.link
B.leave
C.find
D.a(chǎn)ttract
小題7:
A.enjoy
B.a(chǎn)ttend
C.handle
D.a(chǎn)ppreciate
小題8:
A.similar to
B.due to
C.rather than
D.more than
小題9:
A.rejected
B.lacked
C.stole
D.a(chǎn)ssessed
小題10:
A.blessings
B.orders
C.guides
D.treats
小題11:
A.a(chǎn) peaceful world
B.each other
C.delicious food
D.happy time
小題12:
A.colorful
B.dark
C.strange
D.splendid
小題13:
A.step
B.minute
C.time
D.moment
小題14:
A.in case
B.even if
C.a(chǎn)s well as
D.so that
小題15:
A.comfortable
B.sick
C.cautious
D.thrilled
小題16:
A.hoped
B.dreamed
C.feared
D.loved
小題17:
A.thinned
B.increased
C.swelled
D.a(chǎn)pproached
小題18:
A.came forward
B.set off
C.broke away
D.sat down
小題19:
A.over and over again
B.for one thing
C.one last time
D.here and there
小題20:
A.shaking
B.smiling
C.leaving
D.praying

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:完形填空

閱讀下面短文,掌握其大意,然后從下列各題所給的四個(gè)選項(xiàng)(A、B、C和D)中,選出最佳選項(xiàng),并在答題卡上將該項(xiàng)涂黑。
I was in a department store with my mom, aunt, and my sister a few days ago.   61 , I am one of those people who do not like to go shopping with my family. However, I decided this time to   62  them.
My aunt and I were   63 for some things to buy for our family when I noticed two   64 on the side. One of them had a little girl sitting on it with her  65 nearby and the other one was  66 . So, I decided to sit down. While I was   67 my own thing there, I  68 that the family were not in front of the   69 anymore. I saw the girl  70 and look around for her family. She came back and I saw her in  71 , crying.
I knew that she  72 her family and was all by herself . Now, I am sure that almost everybody has been lost in a department store or   73 big before and we all know that feeling.   74 I went up to her and asked what was   75 and in between tears she told me she was lost. I   76 her a smile card I just bought. You should have seen the  77  on her face when she read it. Then I went up to customer service center and  78 them what happened. People there promised to  79 her. After I left, the little girl’s parents went there and I could see them looking around for the person who had found their daughter and given her the   80 . Little did they know it was a regular teenager who did it.
小題1:
A.LuckilyB.UsuallyC.SadlyD.Surprisingly
小題2:
A.helpB.encourageC.joinD.support
小題3:
A.a(chǎn)nsweringB.lookingC.preparingD.calling
小題4:
A.chairsB.childrenC.signsD.toys
小題5:
A.friendsB.bookC.familyD.bags
小題6:
A.cleanB.largeC.emptyD.beautiful
小題7:
A.studyingB.carryingC.buyingD.doing
小題8:
A.noticedB.believedC.doubtedD.understood
小題9:
A.shopB.giftC.girlD.lady
小題10:
A.get upB.come upC.give upD.make up
小題11:
A.returnB.detailC.vainD.tears
小題12:
A.hatedB.raisedC.lostD.lived
小題13:
A.somewhereB.somethingC.everywhereD.everything
小題14:
A.IfB.AsC.SoD.Or
小題15:
A.importantB.wrongC.strangeD.different
小題16:
A.lentB.gaveC.sentD.posted
小題17:
A.smileB.hopeC.puzzleD.worry
小題18:
A.remindedB.warnedC.a(chǎn)skedD.told
小題19:
A.look out forB.take care ofC.wait forD.call up
小題20:
A.courageB.moneyC.explanationD.card

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:閱讀理解

I used to work in an office, which had a Iocust tree growing outside the window. It had grown into a tall tree and must have been there for a long time. The tree blocked the view and made the office seem dull. Unfortunately, this happened to be the room assigned to me, and l was depressed by it for quite some time.
When the first spring came, everything was green except the locust tree.I felt very happy because I had thought it had died!
One morning, when I opened the window for some fresh air, I unexpectedly smelt a familiar sweet scent floating into my office which I could not name. Suddenly,I realized it was the locust tree!The tree that I thought dead was in full bloom!
From then on, I usually came to the office very early to see dew forming on the locust tree blossoms, and was eager to see spring again every year.
During summer, the green leaves provided shade protecting me from the harsh sunlight, but allowing enough light in to make it pleasant. In autumn, the leaves turned many different colors. Its beauty touched my soul. Many times, I thought to take photos but never did. Then, I had to leave in a hurry. Later in life, it became a great regret that I had not done so.
Actually, many times in our lives we think we own something and thus do not value it. We don't feel regretful until we lose it one day! Moreover, sometimes, we have to accept the things we don't want and need to discover the hidden beauty to find unexpected joy!
小題1: The locust tree first attracted the author most by____.
A.the way it blocked the viewB.its height
C.the smell of its flowersD.its green leaves
小題2:In which season do you think the author paid the least attention to the locust tree?
A.Spring.B.SummerC.Autumn.D.Winter.
小題3:Which of the following statements is true of the author according to the passage?
A.He would have regretted if the locust tree had died as he had thought it had.
B.The locust tree turned out to be a lovely memory for him.
C.He felt unhappy as he had forgotten to take the photos with him.
D.His work in the office changed with the seasons every year.
小題4:It can be inferred from the passage that _______.
A.the locust tree died soon after the author left the office
B.the author worked in the office for at least a few years
C.it was summer when the author took his job in the office
D.the weather was dry when the author first saw the tree
小題5:What advice does the author intend to give us?
A.Treasure what we've owned.B.Look before you leap.
C.Treat everything calmly.D.Never forget the past.

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:閱讀理解


When families gather for Christmas dinner, some will stick to formal traditions, that is, their tables will be set with the good dishes and silver bowls. But now in many other homes, this china-and-silver elegance (優(yōu)雅)has given way to a stoneware (粗陶) and informality, with dresses in an informal and ordinary look. For hosts and guests, the change means greater simplicity and comfort. For makers of fine china in Britain, it means economic hard times.
Last week Royal Doulton, the largest employer in Stoke-on-Trent, announced that it is removing 1,000 jobs -- one-fifth of its total workforce. That brings to more than 4, 000  the number of positions lost in 18 months in the pottery (陶瓷) field. Wedgwood and other pottery factories made cuts earlier.
Although a strong pound and weak markets in Asia play a role in the downsizing, the layoffs(失業(yè)) in Stoke have their roots in great social changes. A spokesman for Royal Doulton admitted that the company "has been somewhat slow in catching up with the trend(潮流)" toward informal dining. Families eat together less often, he explained, and more people eat alone, either because they are single or because they want to eat in front of television. Even dinner parties, if they happen at all, have gone informal. In a time of long work hours and busy family schedules, busy hosts insist, rightly, that it's better to share a takeout pizza on paper plates in the family room than to wait for the perfect moment or a "real" dinner party. Too often, the perfect moment never comes. Iron a fine-patterned tablecloth? Forget it. Clean the silver bowls ? Who has time?
Yet the loss of formality has its down side. The fine points of etiquette (禮節(jié)) that children might once have learned before at the table by observation or instruction from parents and grandparents (" Chew with your mouth closed." "Keep your elbows off the table. ") must be picked up else-where. Some companies now offer etiquette courses for employees who may be able professionally but inexperienced socially.
71. In many homes nowadays, people tend to ______________________
A. stick to formal traditions when they dine
B. set their tables with the good dishes and silver bowls
C. have dinner informally
D. buy many sets of fine china
72. Why do people tend to follow the trend towards informal dining?
A. Family members need more time to relax.
B. Busy schedules leave people no time for formality.
C. People prefer to live a comfortable life.
D. Young people won't follow the etiquette of the older generation.
73. It can be learned from the passage that ‘Royal Doulton’ is              .
A. a store of steel tableware                 B. a store of stoneware
C. a store of pottery chain                 D. a producer of fine china
74. The main cause of the layoffs in the pottery industry is              .
A. the increased value of the pound          B. the worsening economy in Asia
C. the change in people's way of life         D. the fierce competition at home and abroad
75. In the last paragraph, we can find that formal table manners, though less popular than before in present social life,               .
A. are still a must on certain occasions       B. are certain to return sooner or later
C. are still being taught by parents at home   D. can help improve personal relationships

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:閱讀理解

Every day millions of letters go from one country to another. Letters mailed in Italy are received in Japan. Letters mailed in Canada are received in Africa. On the letters are many different kinds of stamps,bought in different countries.
The Universal Postal Union helps each letter get to the right place as quickly as possible. It sets up rules about the size and weight of letters,postcards,and small packages(包裹). It has rules that all countries must follow about international postal rates(費(fèi)用).
One hundred years ago,international mail did not move so smoothly. One country did not always accept another country’s letters. Letters from some countries were too large to fit into the mailboxes of other countries. Letters travelled by many different routes(路線).Some were lost along the way.
Sometimes the person who sent the letter could pay only part of the postage. The person receiving the letter had to pay the rest.
The United States was the first to suggest that all countries work together to settle the questions of international mail. In 1974,men from twenty-four countries met in Switzerland to form the Universal Postal Union.Today,more than 120 nations belong to this union. From its office in Switzerland,the union helps the mail to move safely and quickly around the world.
小題1:From the story we can infer that ______.
A.mail is important to all countries
B.not enough letters are sent all over the world
C.a(chǎn)ll the letters must go to Switzerland first
D.a(chǎn)ll stamps look exactly the same
小題2:The Universal Postal Union was formed ___________________ .
A.to help move mail quickly around the world
B.to give many men a chance to work
C.to help men meet in Switzerland
D.to look for the lost letters along the way
小題3:The underlined word “postage” in this passage means __________ .
A.money paid when you buy a stamp
B.money spent on an envelope
C.the charge for carrying a letter by post
D.the pay a postman receives for his work
小題4:This passage is mainly about ______________ .
A.different kinds of stamps in different countriesB.a(chǎn)n organization that makes rules
C.international mailD.the size and weight of letters

查看答案和解析>>

科目:高中英語(yǔ) 來(lái)源:不詳 題型:閱讀理解


The summer vacation is over. It is true that time always flies fast. During the vacation , the weather was bad and I could not do much work, but I live happily.
As the afternoon was hot, I did my work in the morning. I used to get up at 6:30 and take a walk in the garden for half an hour. After breakfast, I began reading English and Chinese and did some exercises in maths. This took me three hours or more. I worked quite hard and made good progress.
I spent the afternoon outside. I went to swim and it was very funny. I would not go home until it was five or six o’clock. Sometimes a friend would come to see me and we would spend some hours listening to music.
In this way, I spent my vacation happily. And I not only studied well but also became a good swimmer. Now I am in good health and high spirits.
60. What does the text tell us?
A. How the writer spent his summer vacation.
B. What the weather was like in the summer.
C. When the writer got up in the morning.
D. Where the writer took a walk.
61.The writer spent most of the afternoon _______.
A. listening to music    B. visiting his friends    C. walking in the garden   D. swimming 
62. The writer had very good summer holidays because he ______.
A. worked very hard and made good progress
B. learned to swim and did his work well
C. got up early and went home late
D. liked swimming better than studying
63.Which of the following is NOT true?
A. The writer made progress in his lesson.
B. The writer took a walk for half an hour before breakfast
C. The writer began studying as soon as as he got up.
D. The writer spent more time swimming than listening to music.

查看答案和解析>>

同步練習(xí)冊(cè)答案