The color red often means danger -- and by paying attention, 1 can be prevented. At railroad crossings, flashing red lights warn cars to stay back. A red light at a traffic intersection tells cars to stop, so 2 dont run into other cars.
In the future, the color red also may help prevent danger3construction sites. Thanks to new work by engineers, bridge supports- or other kinds of materialscould one day contain a color-changing material. It will turn red 4a structure collapses or falls 5 A tiny molecule may make a big difference in future warning systems.
A polymer6 a color-changing molecule called a mechanophore turns red seconds before it snaps. The technology may one day allow damage to materials or structures to be easily 7 .
The secret behind the color-changing material is a particular type of molecule. A molecule is a group of atoms held together by8bonds. Molecules come in all shapes and sizes, and make up 9you can see, touch or feel. How a molecule behaves depends on what kinds of atoms it contains, and how theyre held together.
When a polymer containing a color-changing molecule called a mechanophore is about to breaks, it produces a color. When a polymer with mechanophore molecules becomes injured or10, one of the mechanophore bonds breaks and the material turns red. Its a really simple detection method, says Nancy Sottos, one of the scientists who worked on the project. Were 11 up this one bond, and it changes color. Sottos and her team tested the color-changing polymers in their lab. The test12 proved encouraging.
There is a way to get rid of the red color: 13. When a bright light is shone on the mechanophore, the broken bond is fixed - and the red color disappears. This self-healing may be a problem for engineers. They need to use the color-changer in big construction projects that will be 14 , in sunlight. And sunlight will make the mechanophores warning system useless.
Sottos and her fellow scientists still have15 work to do before the color-changing molecules can be used outside the lab.
练习:
1. A measures
B accidents
C actions
D collapses
2. A they
B it
C some
D most
3. A with
B over
C at
D in
4. A before
B after
C once
D while
5. A together
B behind
C down
D apart
6. A contacting
B conducting
C containing
D considering
7. A controlled
B spotted
C repaired
D changed
8. A technical
B electronic
C physical
D chemical
9. A everything
B something
C nothing
D anything
10. A weak
B strong
C tough
D soft
11. A using
B opening
C turning
D finishing
12. A laws
B theories
C tools
D results
13. A air
B electricity
C light
D sound
14. A aside
B beside
C inside
D outside
15. A a part of
B a pair of
C a piece of
D a lot of
参考答案 BACAD CBDAA BDCDD
2016届高三英语(北师大版)一轮复习课件:Unit 19 Language19-1
2016届高三英语(北师大版)一轮复习课件:Unit 9 Wheels9-1
2016届高三英语(北师大版)一轮复习课件:Unit 5 Rhythm5-1
2016届高三英语(北师大版)一轮复习课件:Unit 13 People 13-1
2016届高三英语(北师大版)一轮复习课件:Unit 15 Learning15-1
2016届高三英语(北师大版)一轮复习课件:Unit 17 Laughter17-1
2016届高考英语一轮复习课时规范训练:Module1《British and American English》外研版必修5
2016届高考英语一轮复习课时规范训练:Module6《Old and New》外研版必修3
2016届高三英语(北师大版)一轮复习课件:Unit 12 Culture Shock12-1
2016届高三英语一轮复习题组层级快练:(一)外研版必修1
2016届高考英语一轮复习课时规范训练:Module1《Life in the Future》
2016届高考英语一轮复习课时规范训练:Module5《The Great Sports Personality》外研版必修5
2016届高考英语一轮复习课时规范训练:Module6《War and Peace》外研版选修6
2016届高考英语一轮复习课时规范训练:Module4《Music Born in America》外研版选修7
2016届高三英语(北师大版)一轮复习课件:Unit 14 Careers14-1
2016届高三英语(北师大版)一轮复习课件:Unit 16 Stories16-1
2016届高考英语一轮复习课时规范训练:Module6《Unexplained Mysteries of the Natural World》外研版必修4
2016届高三英语(北师大版)一轮复习课件:Unit 21 Human Biology21-1
2016届高考英语一轮复习课时规范训练:Module4《Sandstorms in Asia》
2016届高三英语(北师大版)一轮复习课件:Unit 11 The Media 11-1
2016届高三英语(北师大版)一轮复习课件:Unit 23 Conflict 23-1
2016届高三英语(北师大版)一轮复习课件:Unit 4 Cyberspace4-1
2016届高考英语一轮复习课时规范训练:Module1《Europe》外研版
2016届高三英语(北师大版)一轮复习课件:Unit 7 The sea7-1
2016届高考英语一轮复习课时规范训练:Module6《The Tang Poems》2 外研版选修8
2016届高考英语一轮复习课时规范训练:Module2《Developing and Developed》
2016届高三英语(北师大版)一轮复习课件:Unit 24 Society 24
2016届高三英语(北师大版)一轮复习课件:Unit 14 Careers14-2
2016届高考英语一轮复习课时规范训练:Module2《Fantasy Literature》
2016届高三英语(北师大版)一轮复习课件:Unit 18 Beauty18-1
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英语课件 |
英语试题 |
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