Wonder Webs
Spider webs are more than homes, and they are ingenious traps. And the worlds best web spinner may be the Goldern Orb Weaver spider. The female Orb Weaver spins a web of fibers thin enough to be invisible to insect prt, yet _____1____ enough to snare a flying bird without breaking.
The secret of the webs strength? A type of super-resilient ____2____ called dragline. When the female spider is ready to ____3_____ the webs spokes and frame, she uses her legs to draw the airy thread out through a hollow nozzle in her belly. Dragline is not sticky, so the spider can race back and forth along ____4___ to spin the webs trademark spiral.
Unlike some spiders that weave a new web every day, a Golden Orb Weaver _____5_____ her handiwork until it falls apart, sometimes not for two years1. The silky thread is five times stronger than steel by weight and absorbs the force of an impact three times better than Kevlar, a high-strength human-made ____6____ used in bullet-proof vests. And thanks to its high tensile strength, or the ability to resist breaking under the pulling force called tension, a single strand can stretch up to 40 percent longer than its original _____7____ and snap back as well as new. No human-made fiber even comes ____8____.
It is no ____9____ manufacturers are clamoring for spider silk. In the consumer pipeline: high-performance fabrics for athletes and stockings that never run2. Think parachute cords and suspension bridge cables. A steady _____10_____ of spider silk would be worth billions of dollarsbut how to produce it? Harvesting silk on spider farms does not ____11_____ because the territorial arthropods have a tendency to devour their neighbors.
Now, scientists at the biotechnology company Nexia are spinning artificial silk modeled after Goldern Orb dragline. The ____12____ step: extract silk-making genes from the spiders. Next, implant the genes into goat egg cells. The nanny goats that grow from the eggs secrete dragline silk proteins in their ______13____ . The young goats pass on the silk-making gene without____14____ help from us, says Nexia president Jeffrey Turner. Nexia is still perfecting the spinning process, but they hope artificial spider silk will soon be snagging customers ____15____ the real thing snags bugs.
1. A) tough B) soft C) large D) smooth
2. A) cloth B) silk C) nylon D) wool
3. A) repair B) pull C) move D) weave
4. A) him B) her C) it D) those
5. A) refixes B) reproduces C) remakes D) reuses
6. A) metal B) mass C) material D) model
7. A) bredth B) length C) height D) strength
8. A) close B) well C) open D) awake
9. A) hurry B) worry C) wonder D) use
10. A) shipment B) supply C) run D) exchange
11. A) run B) go C) deal D) work
12. A) previous B) foremost C) first D) front
13. A) milk B) meat C) lungs D) muscle
14. A) no B) any C) some D) many
15. A) as fast as B) as gently as C) as fully as D) as little as
参考答案:ABDCD CBACB DCABA
娱乐资讯:费德勒姐妹温网夺冠赔率1赔100
时尚小魔女:阿汤哥爱女苏芮
娱乐资讯:苏珊•波伊尔:名利是"毁灭之球"
双语科技百科(近现代成就) 第112期:长征三号
娱乐时尚:珍妮弗安妮斯顿成为《时尚芭莎》封面女郎
[娱乐时尚] 电话的末日
娱乐时尚:维多利亚患"厌食症"? 骨瘦如柴似骷髅
苹果拟强化用户iCloud备份的加密
娱乐时尚:艾薇儿甩掉朋克 性感亮相时装周
娱乐时尚:不老妮可基德曼也尝试"拉皮"?
[娱乐时尚] 09全球青年富翁榜前五位
[娱乐时尚] 您的私人睡眠教练
娱乐资讯:为降"伏地魔"美国哈迷涂鸦路标
娱乐时尚:哈利波特魔力不凡 乖乖女赫敏大变身
明星示范时尚优雅通勤装
历届“邦女郎”性感比拼
娱乐时尚:看奥巴马如何过结婚纪念日
娱乐时尚:哈利波特新动向
娱乐时尚:汤姆克鲁斯:全家时尚总动员
娱乐时尚:艾美奖精彩瞬间剪影
娱乐时尚:看外国人如何形容闭月羞花之貌
娱乐时尚:奥巴马白宫秀剑术
[娱乐时尚] 哪些品牌最受女性青睐?
[娱乐时尚]迈克尔杰克逊之子与克林顿总统的忘年交
[娱乐时尚] 迈克尔杰克逊生前曾高价造氧舱,欲活150岁
娱乐时尚:搞怪的2009另类诺贝尔奖获奖名单
[娱乐时尚] 间歇性训练法减肥更快?
小米5正式发布 相关人士却大多不看好!
[娱乐时尚]《时代》十问好莱坞著名演员阿尔·帕西诺
娱乐时尚:萨科奇大汗淋淋纽约晨跑
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |