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
挑战动物起源理论 丹麦海绵需氧极少
人造鸡蛋将走向世界 口感与真鸡蛋无异
印度法官裁定婚前性行为“反宗教”
移动技术:“韩流”的推手
多部华语电影入围2017年柏林电影节
为什么快餐正在慢慢地夺去你的生命?
研究揭示幸福婚姻秘诀:每周说10次“我爱你”
“母亲”译为“母狗”:斯里兰卡为翻译错误致歉
英国王子以身作则 投身抗洪救灾
拒绝当狼爸虎妈 如何避免冲孩子发脾气
准备离职时当心你的手机数据
科技在发展 可夹在衬衫上的袖珍相机
理财小贴士:大学生省钱的十大妙招
想成功?你需要逼自己做的19件难事
反情人节运动引关注:到电影院买光单座票
白宫前女义工:希拉里抹黑受害人
爱的教育:真爱教会我们的17堂课
马年说“马”
一生中应该有的八种类型的朋友
奥巴马4月访日菲等四国 重振亚太战略
比特币ATM机将登陆美国
节后离职潮:六招让简历更有实力
十个原因告诉你 为什么你的朋友那么少
美网站出售“人体脂肪” 网友赞其“减肥利器”
安全重要还是点赞重要? 走路时请别看手机
赛百味被曝面包含橡胶鞋底成分 称中国区未用
无免费Wi-Fi成游客抱怨新问题
体坛英语资讯:China confirm 13-player squad for Asian Table Tennis Championships
Facebook推56种性别选项 你会选哪一种?
正是门当户对的婚姻拉大了社会收入差距
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |