Broken rubber bands and flat tires requiring replacement could soon be a thing of the past.
French researchers have developed a new kind of rubber that can repair itself when broken.The new rubber is made from widely available materials including vegetable oil and a common industrial chemical.All the materials are considered safe to the environment and can be easily reused.
The best part is that the new rubber can be repaired and used again and again without losing its strength or ability or stretch.When cut, the rubber can be made new again, simply by pressing the two broken ends back together.
The product can be repaired at room temperature, around twenty degrees Centigrade;other self-healing materials require higher temperatures for repair.
Traditionally, rubber substances are made from huge molecules(分子)connected by strong chemical links, or bonds.The new rubber is made of smaller molecules.The molecules are linked together using hydrogen bonds.When connected in this way, the molecules act like one long molecule, forming what is called supramolecular networks(超分子网).When the rubber is cut, the molecules attempt to connect with whatever molecule is near them.When pressed together, the molecules are able to repair themselves at the molecular level, making the repaired rubber like new.
However, time is an important element in the process.If the broken ends are not brought together quickly, a repair is not possible.This is because molecules will form bonds with molecules on their own side.The inventors say the surfaces of the rubber can be repaired within a week of being separated.
The rubber is the creation of scientists at the Industrial Physics and Chemistry Higher Education Institution in Paris.The organization is part of France's National Center for Scientific Research.The new material is described in greater detail in the research publication Nature.
1.According to the introduction, which of the following is NOT the advantage of the new rubber?
A.It can be made as easily as common rubber.
B.It is environmentally-friendly.
C.It can repair itself at room temperature.
D.It is made of smaller molecules.
2.What does the 5th paragraph mainly tell us?
A.Why the new rubber is unique.
B.Why the new rubber can repair itself.
C.The new rubber is made from huge molecules.
D.The new rubber is different from the common rubber.
3.If we want to know more about the technology of this kind of new rubber, where can we get the information?
A.In the researchers' diary. B.In a guide book.
C.In a research magazine. D.In a newspaper.
A very little boy was spending his Saturday morning playing in his sandbox. He had with him a plastic pail (桶) and a shiny, red plastic shovel (铲). In the 1 of creating roads and tunnels in the sand, he 2 a large rock in the middle of the sandbox.
The boy dug around the rock, 3 to move it off the dirt. At first, he wanted to carry it out of the sandbox with his hands; however, it was too heavy. Later, with much 4 , he pushed the rock across the sandbox by 5 his hands. When the boy got the rock to the 6 of the sandbox, he found that he couldn’t roll it up and 7 the little wall. 8 , the little boy pushed, but every time he thought he had made some 9 , the rock tipped (翻滚) and then fell back into the sandbox. The little boy pushed and pushed, but his only 10 was to have the rock roll back.
Finally he 11 tears. All this time the boy’s father watched from his living room window 12 the drama was unfolded. The moment the tears fell, a large 13 appeared across the sandbox. It was the boy’s father. Gently but 14 , he said, “Son, why didn’t you use all the strength that you had?”
Defeated, the boy 15 back, “I did! I did! I used all the strength that I had!”
“No, you didn’t. You didn’t ask me for help.” The father 16 down, picked up the rock and dropped it off the sandbox.
Do you have “rocks” in your life that need to be 17 ? Are you discovering that you don’t have 18 it takes to lift them? There is someone who is willing to give us the 19 we need. Maybe, it’s sometimes a good idea to ask others for 20 when we meet difficulties we can’t overcome.
1. A.method B.step C.practice D.process
2. A.created B.set C.discovered D.brought
3. A.trying B.managing C.deciding D.competing
4. A.thought B.struggle C.movement D.worry
5. A.touching B.shaking C.using D.controlling
6. A.bottom B.center C.edge D.front
7. A.over B.down C.through D.into
8. A.Doubted B.Surprised C.Pleased D.Determined
9. A.attempt B.progress C.effort D.decision
10. A.hope B.reward C.point D.purpose
11. A.made out B.broke out C.burst into D.rushed into
12. A.so B.as C.until D.before
13. A.rock B.picture C.figure D.shade
14. A.surprisingly B.doubtfully C.kindly D.firmly
15. A.shouted B.smiled C.called D.asked
16. A.reached B.looked C.fell D.put
17. A.pushed B.dropped C.carried D.removed
18. A.who B.what C.which D.where
19. A.minds B.spirits C.force D.strength
20. A.help B.tips C.advice D.ideas
_____ anyone phone during the board meeting, please tell them I am busy.
A.Should B.Will C.May D.Can
Tom Hopper got his work _____ in the filming industry for his film had been crowned best picture at the Oscars.
A.to recognize B.recognizing C.recognize D.recognized
If our product ____ unsatisfactory within 7 days in any way, you can take it back.
A.shows B.proves C.makes D.performs
--Mum, I don’t think I am qualified enough to do this.
--Honey, be confident! You should know it is ____ a man thinks of himself ___ really determines his fate.
A.that; that B.how; that C.what; that D.how; how