American scientists have developed the first material that repairs itself. The material is a form of plastic that has been engineered to fill breaks in its surface.
Plastics are used today in everything from airplane wings to hundreds of object found in the home. Scientists wanted to find a way to make objects made of plastic last longer. The researchers hope their new discovery can be used to make objects that are difficult or impossible to replace.
The surface of plastic objects breaks over time. Very small breaks develop every time a plastic object is used. The researchers wanted to find out how to stop plastic from developing small breaks that weaken and destroy it. They found the answer in the chemical structure（构造）of plastic itself.
Plastic is made of monomers（单体）. These monomers link together to form polymers（聚合物）. Polymers give plastic its ability to be shaped and its strength. The research team found a way to make plastic that contains very small balloons filled with monomer liquid（液体）. When the new plastic cracks（裂开）, the monomer liquid is let out and flows into the crack. Thus the break is repaired. The repaired plastic has seventy – five percent of the strength of undamaged plastic.
The new self – repairing plastic is not yet ready for production. But it has several possible uses. One could be in space vehicles where parts cannot be repaired or replaced. Another possible use might be in bridges. And it could be used in people, to replace bone joints that have become broken or damaged.
72．Which of the following can be the best title for the article?
A．Ever-Lasting Material Invented.
B．The Chemical Structure of Plastic.
C．Plastic that Repairs Itself.
D．Small Balloons that Makes Plastic Stronger.
73．We know from the passage that the repair is done as .
A．the cracked plastic parts are changed
B．the plastic is made
C．the liquid is put into the plastic cracks
D．the plastic cracks
74．The scientist are planning to use the new material in space vehicles, bridges and people because .
A．the plastic parts in them are required to last longer
B．the plastic parts in them are easily broken or damaged
C．the new material cannot be used elsewhere
D．they want to experiment in these places first
75．What can we know about the new material mentioned in the passage?
A．It is a kind of liquid that is commonly used.
B．It is more difficult to make than common plastics.
C．Its surface does not crack so easily as other ones.
D．It makes it difficult or impossible to replace plastic objects.
Why should I teach my children history? That sounds like a stupid question to even ask. But, as I hear different home schooling teachers discuss history, I get the idea that there may be different reasons for teaching history. Let me briefly explain the three good reasons for studying history and two bad reasons for studying history.
The major reason I see for studying history is that we can learn from the past. I am convinced that the world would be a much better place if more people understood the successes and failures of the past and the things that made these successes and failures. However, as the unfortunately true statement goes "the one thing we seem to learn from history is that we don't seem to learn from history." Perhaps at least in teaching history, to my children I can do a small part in changing this.
The second major reason for studying history is that it is hard to understand the current political climate in the absence of an understanding of its historical context. We can not even understand why we are and where we are without history, much less (更不必说) try to figure out where we are going or how we should get where we want to be.
I teach my children history, for one more reason. I purchased a set of historical audio (录音机) tapes for our children. My seven-year-old son listened to them over and over. It was my hope that he would become inspired by the accomplishments of people like the Wright brothers to accomplish things by himself. I think that it is good that we celebrate the accomplishments of people like Martin Luther King Jr. if, in doing so, young people are called on to stand for the principles that he stood for and accomplish what he accomplished. I also think that by studying people like Adolph Hitler, people can learn to stand against the things that he stood for. In Paragraph 3, the author shows that history is useful because _______________.
| A．it makes the current political situation go smoothly |
| B．it helps us realize the importance of historical events |
| C．it helps us understand why things are the way they are |
| D．it helps people accept the present situation where they live |
Some historical figures(人物) are mentioned in the last paragraph to show ______________.
| A．people can be inspired to do good, while also learning to fight against evil |
| B．people may also learn from bad historical figures |
| C．more celebrations should be held to honor their achievements |
| D．today’s people can also achieve what they achieved |
What would be talked about in the following paragraph?
| A．How to teach history effectively. |
| B．Some negative reasons for studying history. |
| C．How to get more people to study history. |
| D．Some bad historical figures. |
The main purpose of this passage is to ____________.
| A．inspire the parents to teach their children history |
| B．show the importance of history in politics |
| C．explain the reasons why children study history |
| D．introduce the writer' s own way of teaching history |
Put your car keys away and forget about your travel pass --- it’s time to do a bit of walking.
National Walking Month is organized every May by Living Streets, an organization that campaigns for the rights and the needs of pedestrians, so the organization is previously known as the Pedestrians’ Association. The association’s aim is to make streets safe, attractive and enjoyable spaces for people to live, work, shop and play. By putting people (rather than vehicles) first, Living Streets wants to create streets and spaces where people feel happier, healthier and more sociable.
The annual campaign gives participants a great opportunity to experience the many virtues of walking. These include the physical health benefits of becoming fitter; the environmental advantages of not using vehicles; the delight of local discoveries --- seeing more of your local areas on foot; the enjoyment of walking with other people, whether family, friends or work colleagues and finally the stress relief that comes from walking --- walking can clear your head.
Walk to School Week, 18 to 22 May, is part of the month’s activities and its aim is to encourage parents to send children to school on foot, rather than take them in the car or let them use public transport. The movement was started in 1995 with only five participating schools and now two decades later, more than one million children take part.
Similarly, there is Walk to Work Week, 11 to 15 May, where grown-ups are encouraged to walk. In the morning, getting off the bus a stop early or parking a few streets away is a good way to add more steps to the daily total. And during the working day, after having lunch at the desks or in the canteen, take a walk and get some fresh air. Walk home with your workmates and chat away about everything under the sun but work!What’s the purpose of Living Streets?
| A．To let people keep away from vehicles. |
| B．To build safer walkways for pedestrians. |
| C．To help people enjoy walking in the street and enjoy life. |
| D．To make people aware of environmental pollution. |
Paragraph 3 is intended to show that walking is __________.
| A．so interesting | B．very relaxing |
| C．perfectly safe | D．highly beneficial |
What can we learn from Walk to School Week?
| A．It is organized by the government. |
| B．It is held before Walk to Work Week. |
| C．It has developed rapidly over the last 20 years. |
| D．It encourages students to walk to school alone. |
What’s the main idea of the last paragraph?
| A．An introduction to Walk to Work Week. |
| B．A nationwide health movement. |
| C．The influence of working day. |
| D．National Walking Month’s history. |
Sunday, 31 August
We’ve been in China for a month now. Dad, Mom, Harry and I moved to Tianjin on 25 August. We’re not very far from Beijing. Two days ago, we celebrated my 16th birthday. It was great celebrating in China; the only thing that was strange was the cake--here they’re not as sweet as the ones in New York. On Monday school starts—I wonder what it will be like.
Monday, 1 September
On my first day I was looking around for a locker to put my books in. However, here all the students keep all of their books at their desks--we stay in the same classroom because apparently we don’t have to go from class to class--teachers come to us!
Today we selected teacher assistants for each subject. Their duties are to collect homework, make announcements, and do other stuff for the teacher and the students. It’s kind of a big deal here! Since I am from the US, I was asked to be the English assistant. I felt so proud but quite nervous at the same time because I wasn’t sure what I had to do, but I accepted the job anyway.
Friday, 3 October
Boy, what a week! Now we have nine classes every day, including the morning class, a combination of our American schools’ “Homeroom” and “Study Hall”. I think Chinese students work too much! I have to do my homework when I get back home. I don’t even have time to watch TV or surf the Internet like before. I sometimes miss New York and my school because we didn’t have to study so much. We had more time to hang out with our classmates and neighbors; here, besides their usual classes, students are involved in weekend classes in subjects such as English, Chinese and math.
I get a lot of attention, being from another country. Everyone wants to practice English with me! A really cute girl even asked me for my phone number on my second day and sent me a text message! I’m making a lot more friends now. I just need a lot of help to improve my Chinese. Some students want to do a language exchange program with me. Nice!
The passage mentions all the following points EXCEPT .
| A．physics study | B．teacher assistants |
| C．free time activities | D．language exchange program |
According to the passage, which of the following is NOT the teacher assistant’s duty?
| A．Collecting homework. |
| B．Making announcements. |
| C．helping teachers with small errands（差事） |
| D．Teaching classmates. |
Where is this passage most probably from?
| A．A story book. | B．A guide book. |
| C．A diary. | D．A magazine. |
The passage is best described by ________.
| A．culture shock. | B．multi-culture. |
| C．unique culture. | D．culture background |
Do you love Beats headphones, True Religion jeans, and UGG shoes? These are some of the most popular brands (牌子) around. They are also expensive. But some experts say they are not much better than cheaper brands.
For example, Jim Wilcox works for Consumer Reports. He tested all kinds of headphones. He says that $80 Koss Pro headphones provide basically the same quality and comfort as Beats. So why do people pay twice or even 10 times as much for the hottest brands?
Experts say it's because fashionable, expensive brands send a message. Brands say “I belong” or “I can afford it.”
Some people think that expensive brand names are worth the price. They say that some designer clothes really are top quality and that they last longer than cheaper brands. Some teenagers choose to wear popular brands because these brands make them feel good about themselves.
Alexandra Allam, 17, likes to buy brand-name products. “I'd rather spend the extra money to get something I know I'll be satisfied with,” she says. Her friend Emmy Swan agrees, saying “As long as you can afford it, it seems reasonable to buy what you want.” But not all teenagers agree. “Spending hundreds of dollars for designer sunglasses is stupid and unreasonable,” says Daniel Steinbrecher, 16. “It's fake (假的) happiness.”
People who are against wearing expensive brand names say that many designer brands aren't any better. “It's wasteful to buy things just because they are popular,” says Edmund Williams, 15. “You'll feel better if you buy things because you like them. If you have extra money to spend, it would be better to give it to people in need.”
The example of Jim's report wants to tell us _____.
| A．popular brands make people comfortable |
| B．Koss Pro headphones are better than Beats |
| C．the hottest brands are of the highest quality |
| D．lesser-known brands may offer the same quality as name brands |
According to experts, people choose the hottest brands probably _____.
| A．to show off |
| B．for their better quality |
| C．for their better designs |
| D．to belong to a special group |
What does Edmund think of expensive brands?
| A．They are not worth the price. |
| B．They make him feel confident. |
| C．They need to improve their quality. |
| D．They pay too much attention to personal likes. |
The text is mainly about _____.
| A．how to buy things reasonably |
| B．the competition between brands |
| C．the different values of teenagers |
| D．whether expensive brands are worth high prices |
At times my mom has been uncomfortable seeing these qualities in me. For example，when I was 12，I went to Puerto Rico all by myself to stay with my grandmother for the summer. My mom was extremely nervous about it. She kept telling me how things were different in Puerto Rico，to always put on sunscreen，not to wander away from my grandmother，and other warnings. She helped me pack and did not leave the airport until she saw my plane take off.
But despite her worries，she let me go on my own. As I moved into my teens，she continued to give me space to grow and learn，even when it might have been difficult for her. When I reached my senior year，I decided to move away for college. Once again I found that I differed from my peers：While many of them wanted to stay close to home，I couldn’t wait to be out in the world on my own. While my mom may not have been happy at the thought of my going away，she was supportive and excited for me.
One big thing I realized during my senior year，as my mom granted me more freedom，was that she actually believes in me and trusts me. That means a lot. Most of my life，and especially when I was little，the main person I tried to impress in my schoolwork or other things was my mother. I knew she expected nothing but the best from me. Sometimes it was hard to live up to her standards；getting a single B on my report card would make me feel bad because I knew she wanted me to have all A’s.
I know that her high standards have helped me stay focused on what’s important，like education，and made me who I am. I am thankful for her support and involvement in my life .Most of all I respect her. She is the strongest woman I know and that’s why I have turned out so strong and independent.When the author decided to go to Puerto Rico，his mother________.
| A．wanted to go with him |
| B．worried about his safety |
| C．didn’t allow him to do so |
| D．asked his grandmother for advice |
The author decided to move away for college to________.
| A．be different from his peers |
| B．keep away from his mother |
| C．be independent in the outside world |
| D．make his mother unhappy |
We can learn from the third paragraph that the author’s mother________.
| A．had a high expectation of him |
| B．was too strict with him |
| C．used to expect nothing from him |
| D．cared little about his learning |
In the passage，the author mainly wants to tell us________.
| A．his long way to becoming independent |
| B．his good relationship with his mother |
| C．the importance of a mother’s trust and support |
| D．his mother’s deep love for him |
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