Wonder Webs
Spider webs are more than homes, and they are ingenious traps. And the world’s best web spinner may be the Golden Orb Weaver spider. The female Orb Weaver spins a web of fibers thin enough to be invisible to insect prey, yet____1____ enough to snare a flying bird without breaking.
The secret of the web’s strength? A type of super-resilient____2____ called dragline. When the female spider is ready to____3____ the web’s 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 web’s 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 dollars — but 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 Golden Orb dragline. The____12____ step: extract silk-making genes from the spiders. Next, implant trie 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.
詞匯：
orb 圓狀物 snare 誘捕
snap (網(wǎng))戳破，迅速彈回 resilient 彈回的
dragline (蜘蛛的)避敵絲 spoke輻條
nozzle 噴嘴 trademark 標(biāo)記，特征
spiral 螺旋形 handiwork 手工制品
bullet-proof 防彈的 tensile 可拉長的，張力的
strand 繩，線之一股 clamor 大嚷，強(qiáng)烈要求
pipeline 管道，渠道 stocking 長襪
parachute 降落傘 territorial 領(lǐng)土的，領(lǐng)地的
arthropod 節(jié)肢動物 devour 吞吃
nanny goat 雌山羊 secrete 分泌 snag 抓住
注釋：
1.sometimes not for two years：相當(dāng)于sometimes it does not fall apart for two years。
2.run：(編織物)抽絲
練習(xí)：
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 long as C as fully as D as little as