一級重點 Seeing red Means Danger Ahead (C級)

  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.
  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


  當包含變換顏色分子的機械響應性聚合物要斷裂的時候,它會產生一種顏色。當一個包含機械響應性聚合物分子的聚合物“受損害”或者變弱的時候,其中的一個機械響應性聚合物鍵破碎,這個物質變成紅色。“這是一個很簡單的檢測方法。”Nancy Sottos說,她是為這個項目工作的科學傢之一。Sottos和她的團隊在他們的實驗室測試這種變換顏色的聚合物,測試的結果非常鼓動人心。