全国职称英语等级考试理工类_2012年职称英语理工类完形填空重点文章


政策考试 2019-12-08 22:08:07 政策考试
[摘要]一级重点 Seeing red Means Danger Ahead (C级)The color red often means danger and by paying attention, 1 c

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一级重点 Seeing red Means Danger Ahead (C级)
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 don"t run into other cars.
In the future, the color red also may help prevent danger 3 construction sites. Thanks to new work by engineers, bridge supports or other kinds of materials could one day contain a color-changing material. It will turn red 4 a structure collapses or falls 5 . A tiny molecule may make a big difference in future warning systems.
A polymer 6 a color-changing molecule called a mechanophore turns red seconds before it snaps. The technology may one day allow damage to materials or structures4 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 by 8 bonds. Molecules come in all shapes and sizes, and make up 9 you can see, touch or feel. How a molecule behaves depends on what kinds of atoms it contains, and how they"re 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 or 10 , one of the mechanophore bonds breaks and the material turns red. It"s a really simple detection method, says Nancy Sottos, one of the scientists who worked on the project. We"re 11 up this one bond, and it changes color. Sottos and her team tested the color-changing polymers in their lab. The test 12 proved encouraging.
There is a way to get rid of6 the red color: 13 . When a bright light is shone on the mechanophore, the broken bond is fixed7- 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 mechanophore"s warning system useless.
Sottos and her fellow scientists still have 15 work to do before the color-changing molecules can be used outside the lab.
练习:
1. A measures B accidents C actions D collap-ses
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

答案:BACAD CBDAA BDCDD

看见红色意味着危险在前方
红色常常表示危险,通过引起注意能够防止意外。在铁路交叉口,闪烁的红灯警告车辆靠后。在交通十字路121的红灯告诉车辆停止前进,所以就不会发生车祸。
在未来,建筑工地的红色可能也可以防止危险。多亏了工程师的新作和桥梁支柱等其他的材料,它们有一天能包含一种会变换颜色的物质,该物质能够在建筑物倒塌或之前变成红色。一个小小的分子就会对报警系统起到很大影响。
一个聚合物包含一种变换颜色的分子叫做机械响应性聚合物,它能够在在聚合物断裂前几秒钟变成红色。这项技术能够很容易地发现材料或建筑物的损坏。
这个变换颜色的物质的秘密就是一种特别的分子。一个分子是由化学键把一群原子组合起来。分子有各种各样的形状和大小,所以能够组成你所见到的、摸到的和感觉到的任何东西。一个分子怎样表现取决于它包含什么样的原子,和他们被怎样组合起来。
当包含变换颜色分子的机械响应性聚合物要断裂的时候,它会产生一种颜色。当一个包含机械响应性聚合物分子的聚合物 受损害 或者变弱的时候,其中的一个机械响应性聚合物键破碎,这个物质变成红色。 这是一个很简单的检测方法。 Nancy Sottos说,她是为这个项目工作的科学家之一。Sottos和她的团队在他们的实验室测试这种变换颜色的聚合物,测试的结果非常鼓动人心。
有一种方法可以除去红色:光。当强光照射在机械响应性聚合物上,断裂的键被修复 红色就会消失。这种 自我修复 或许给工程师们带来问题。他们需要在露天的,也就是暴露在阳光下的大建筑工程外面使用换色器。阳光会使机械响应性聚合物的报警系统不起作用。
要让这些变色分子在实验室以外也能使用,Sottos和她的同事们还有许多工作要做。

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