Did you ever wonder why leaves change colors in autumn, or how it happens? Here’s a quick explanation.
First of all, you’ve probably noticed that not all trees lose their leaves. There are two major types of trees: deciduous trees and evergreens. Evergreens keep their leaves and stay green all year long. The deciduous trees are the ones that lose their leaves each year.
In autumn, the days begin to get shorter. The sun is also lower in the sky at noon, which causes temperatures to be cooler. The combination of less sunshine and lower temperatures is what causes the deciduous trees to drop their leaves. In winter, deciduous trees “go to sleep”, sort of like a bear goes into hibernation.
Leaves are the food factories for a plant. Unlike animals，plants make their own food by taking energy directly from the sun. Plants do this by using a chemical in their leaves called chlorophyll.
Chlorophyll is green. During the spring and summer the leaves of a deciduous tree look green because there is a lot of chlorophyll there. In autumn, however, the sunshine becomes more scarce and the leaves on the trees stop making new chlorophyll. As the old chlorophyll starts to break down, the green color of the leaf begins to go away.
You’ve probably also noticed that the leaves of different kinds of trees change different colors. The leaves of some trees turn yellow or orange, while the leaves of other trees turn bright red or purple. The different colors are caused by the different chemical reactions that are happening in the leaves.
For example, the leaves of some trees turn yellow when the chlorophyll breaks down. When the green chlorophyll goes away, a yellow pigment in the leaf becomes visible. The yellow pigment, called cartenoid, was already there during the summer, but is was not easily seen because there was too much green chlorophyll.
In other trees where the leaves turn red or purple a different chemical reaction takes place. In those leaves the chlorophyll also breaks down, but another chemical reaction takes place at the same time. Chemicals in the leaves, called starches, begin to change into chemicals called anthocyanins, which give the leaves their red and purple colors.
So next time you see the beautiful colors of autumn you will also know the science behind that beauty.
46. What is the correct term for trees that lose their leaves in the autumn?
A. Evergreens B. Deciduous C. Cartenoids D. Anthocyanins
47. Which of the following is NOT mentioned as a cause of trees dropping their leaves?
A. A change in temperature B. The amount of daylight available
C. Extra chlorophyll D. Chemical changes in the leaves
48. If there are 50 evergreens and 10 deciduous trees in a forest, in autumn what color are most of the leaves in the forest likely to be?
A. Green B. Red and purple
C. Yellow D. not enough information to determine the answer
49. Which of the following is only present in leaves during the autumn?
A. Chlorophyll B. Starch C. Cartenoids D. Anthocyanins
50. Where would such an article mostly likely be published?
A. In a book B. In a primary school science text book
C. In a magazine for young people D. All are equally likely
Are you an optimist? Do you look at your glass and see it as half full? Do you believe that every cloud has a silver lining and that things generally turn out for the best? Do you believe that if something is meant to be, it will be? If you reply “yes” to all of these questions, then you are an optimist. You probably are enthusiastic, cheerful and outgoing. You may be successful at work and in love.
But you may be misguided because things don’t turn out for the best. You may believe that when one door closes another one opens (for example, you may fail to obtain a new job; another chance will come around soon). Wrong. When one door closes, another door slams (砰然关上) in your face. That’s bitter reality.
Now a book has been published which confirms what pessimists (悲观者) have suspected all along. It’s called The Positive Power of Defensive Pessimism. Its author argues that defensive pessimism can lead to positive results. Defensive pessimism is a strategy used to manage fear, anxiety and worry. Defensive pessimists prepare for the things by setting low outcomes for themselves. They carefully consider everything that may go wrong and plan for ways to handle these problems. And this gives them a sense of control. Lawrence Sanno, a psychology professor, says, “What’s interesting about defensive pessimists is that they tend to be very successful people, so their low opinion of the situation’s outcomes is not realistic. They use it to motivate themselves to perform better.”
So far, so good. This is not rocket science. Defensive pessimists prepare carefully and consider what might go wrong, whether at work, on date or even in a sports game. It makes sense to have a back-up plan. There are many sayings in English urging caution. For example, “Don’t put all your eggs in one basket.” And “Don’t count your chickens until they hatch.” To have a confident and optimistic approach to life’s problems is good. But listen to what Woody Alien, the American comedian says, “Confidence is what you have before you understand the problem.”
There are pros and cons to being an optimist and a pessimist. Don’t feel bad if you see the glass half empty. You are a realist. But lighten up and hook up with someone who sees the same glass half full.What’s the passage mainly about?
| A．A book that has recently been published. |
| B．How to become successful in life. |
| C．The dangers of being too optimistic. |
| D．The benefits of defensive pessimism. |
The underlined sentence “This is not rocket science” (Para. 4) means __________.
| A．it’s not a dangerous thing to do |
| B．it is quite simple to understand |
| C．the cost is not so high |
| D．there is no real proof |
Which of the following English expressions would a defensive pessimist believe?
| A．Don’t put all your eggs in one basket. |
| B．The glass is half full not half empty. |
| C．Whatever will be, will be. |
| D．Every cloud has a silver lining. |
The writer would probably describe himself as __________.
| A．an optimist | B．a defeatist | C．a realist | D．a scientist |
Eddie’s father used to say he’d spent so many years by the ocean, breathing seawater. Now, away from that ocean, in the hospital bed, his body began to look like a beached fish. His condition went from fair to stable and from stable to serious. Friends went from saying, “He’ll be home in a day,” to “He’ll be home in a week.” In his father’s absence, Eddie helped out at the pier (码头), working evenings after his taxi job.
When Eddie was a teenager, if he ever complained or seemed bored with the pier, his father would shout, “What? This isn’t good enough for you?” And later, when he’d suggested Eddie take a job there after high school, Eddie almost laughed, and his father again said, “What? This isn’t good enough for you?” And before Eddie went to war, when he’d talked of marrying Marguerite and becoming an engineer, his father said, “What? This isn’t good enough for you?”
And now, regardless of all that, here he was, at the pier, doing his father’s labor.
Parents rarely let go of their children, so children let go of them. They move on. They move away. It is not until much later, as the heart weakens, that children understand: their stories, and all their accomplishments, sit on top of the stories of their mothers and fathers, stones upon stones, beneath the waters of their lives.
Finally, one night, at his mother’s urging, Eddie visited the hospital. He entered the room slowly. His father, who for years had refused to speak to Eddie, now lacked the strength to even try.
“Don’t sweat it, kid,” the other workers told him. “Your old man will pull through. He’s the toughest man we’ve ever seen.”
When the news came that his father had died, Eddie felt the emptiest kind of anger, the kind that circles in its cage.
In the weeks that followed, Eddie’s mother lived in a confused state. She spoke to her husband as if he were still there. She yelled at him to turn down the radio. She cooked enough food for two. One night, when Eddie offered to help with the dishes, she said, “Your father will put them away.” Eddie put a hand on her shoulder. “Ma,” he said, softly, “Dad’s gone.”
“Gone where?”In Paragraph four, the writer indicates that __________.
| A．Children like moving away from their parents |
| B．Children often feel regretful because they leave their parents |
| C．Children wouldn’t have achieved so much without their parents’ support |
| D．Children can never understand how much their parents have devoted to them |
The underlined sentence “Don’t sweat it” (Para. 6) probably means __________.
| A．Don’t touch it | B．Don’t give it up |
| C．Don’t let him down | D．Don’t worry about it |
Which of the following shows the right order of the story?
a. Eddie’s father died.
b. Eddie married Marguerite.
c. Eddie worked as a taxi driver.
d. Eddie was bored with his father’s job.
| A．dbca | B．dcab | C．bcda | D．bacd |
From the last paragraph, we learn that __________.
| A．Eddie’s mother liked to listen to the radio |
| B．Eddie’s mother missed her husband so much that she was at a loss |
| C．Eddie and his wife lived in his mother’s apartment |
| D．Eddie often helped his mother wash the dishes |
Once upon a time, a man was walking on a mountain when he found an incredible cave with all kinds of treasure inside it. So he gave up his job, his home, and his friends, and spent all his time guarding the cave.
He was so dedicated to it that he hardly ate or drank, and before long he fell ill. One day, when he could hardly move at all, he decided to share the treasure.
He crawled into the cave to get a handful of jewels, but discovered, to his horror, that it was empty except for a small emerald (绿宝石). The man took it and gave it to the first person to come by, a woman.
Then an old man came by. “What bad luck!” the man said. “Just a moment ago I gave a woman the last of the treasure I was guarding.”
“Are you sure there is nothing left?” the old man asked.
The man took him into the cave, where they found a chest with jewels and some bags of gold. The man was shocked, and the old man explained to him, “At last! At last! At last someone has broken the spell of this cave. This is the Cave of Treasure, and you’re the first to have passed its great test. Many have dedicated their lives to this cave, only to end up realizing there was nothing here …”
“And why does this happen?” the man asked.
“This magic cave has only as many riches as your own heart. When someone discovers it, the cave fills with the treasure they bring with them, but later, when they have devoted themselves to guarding the treasure, their hearts become empty, as does the cave. The only way to fill it is by filling your heart with all that is good, as you did by giving the woman that last jewel.”
From that day on, the man understood that it was better to share than to keep. Thanks to the cave and the old man, he became noble and generous.Why did the man give up his job, home and friends?
| A．Because he possessed a variety of treasure. |
| B．Because he devoted himself to a great test. |
| C．Because he had to guard the treasure cave. |
| D．Because he wanted to find the treasure cave. |
What did the man find when he showed his cave to the old man?
| A．All kinds of treasure. | B．A chest with jewels and gold. |
| C．A small emerald. | D．A handful of jewels. |
What do we learn about the people who dedicated their lives to the cave before?
| A．They all found the cave empty at last. |
| B．The old man freed them from its spell. |
| C．They all filled the cave with the treasure they had. |
| D．They thought it was better to share than to enjoy the treasure alone. |
What can we learn from the text?
| A．Different people have different views. |
| B．Treasure only belongs to those who possess it. |
| C．Some people never learn what is really valuable. |
| D．Purely material things cannot make us truly wealthy. |
Writer Jean Stafford scoffed, “Happy people don't need to have fun,” but studies show that the absence of feeling bad isn’t enough to make you feel good；you must try hard to find sources of feeling good. Research shows that regularly having fun is a key factor in having a happy life；people who have fun are 20 times more likely to feel happy.
Recently, I noticed a pattern among activities that people find fun：Have a mission. There’s something about having a playful purpose，of trying to achieve something that makes an activity more fun.
For example a friend told that she loved visiting flea markets（旧货市场）and antique stores to look for old globes-not fancy ones，but cheap ones. She has a rule that she'll never pay more than＄20. She’s the kind of person who loves wandering around in those kinds of shops in any case，but having a mission makes it more fun, less aimless.
For that matter，having a collection of any sort is a very popular way to have a mission. You get satisfaction whenever you find another piece of blue sea glass on the beach or another out-of-print book by Charlotte Yonge in an old bookstore.
Taking photos is a common way to incorporate(使并入) a mission into traveling. Not only does this help keep memories vivid, it also makes you more attuned（协调一致）to your environment while traveling. For example，during my most recent visit to New Haven，I had a lot more fun wandering around once I set myself the mission of taking tourist photos of my own romance.
Why is this true? The First Splendid Truth holds that to be happier，you have to think about feeling good and feeling right，in an atmosphere of growth. The more I’ve thought about happiness，the more surprised I’ve been at the importance of the “atmosphere of growth.” I think this is a huge engine of happiness, and when you have a mission, you create an atmosphere of growth whenever you pursue that mission.
Have you found a way to have a mission? What is it and does it boost your happiness?. According to the author, happy people____
| A．don't need to have fun |
| B．don't have to be occupied with work |
| C．can have 20 times more fun than others |
| D．are always finding sources of feeling good |
. What does the underlined phrase “Having a mission" mean in paragraph 2？
A. Have fun. B. Join in an activity.
C. Find something interesting to do. D: Hunting for a job. The author explains the key factor in having a happy life by____.
| A．making a comparison | B．presenting numbers |
| C．stating common sense | D．using examples |
. What will be probably the best title?
| A．How to live happily |
| B．Where to look for fun |
| C．The importance of feeling good |
| D．Having a mission can make you happier |
A new generation addiction is quickly spreading all over the world. Weboholism（网瘾）, a twentieth century disease, affects people from different ages. They surf the net, use e-mail and speak in chat rooms. They spend many hours on the computer, and it becomes a compulsive habit. They cannot stop, and it affects their lives.
Ten years ago, no one thought that using computers could become compulsive behavior that could affect the social and physical life of computer users. Such behavior has seriously affected teenagers and college students. They are likely to log(写日志) on computers and spend long hours at different websites.
They become hooked（着迷） on computers and gradually their social and school life is affected by this situation. They spend all free time surfing and don’t concentrate on homework, so this addiction influences their grades and success at school. Because they can find everything on the websites, they hang out there. Moreover, this addiction to websites influences their social life.
They spend more time in front of computers than with their friends. The relation with their friends changes. The virtual life becomes more important than their real life. They have a new language that they speak in the chat rooms and it causes cultural changes in society.
Because of the change in their behavior, they begin to isolate themselves from society and live with their virtual friends. They share their emotions and feelings with friends who they have never met in their life. Although they feel confident on the computer, they are not confident with real live friends they have known all their life. It is a problem for the future. This addictive behavior is beginning to affect all the world. .The main idea of the passage is about__________.
| A．the cause of weboholism | B．the advantage of weboholism |
| C．the popularity of weboholism | D．the effect of weboholism |
. We can infer from the passage that_______.
| A．weboholism has the greatest effect on teenagers |
| B．students can hardly balance real and virtual life |
| C．people are addicted to games on the Internet |
| D．virtual life is more vivid and attractive than real life. |
. Which of the following is NOT true of weboholism?
| A．It contributes to the development of the web. |
| B．The chat room language may change social culture. |
| C．The problem will be getting more and more serious later. |
| D．People addicted to the web often become inactive in real life. |