时间：2020-03-10 14:41:45 出处:文达网校
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 neighhors.
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 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 Jeffry 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. sometimes not for two years：相当于 sometimes it does not fall apart for two years
2. run：(编织物 )抽丝
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
1. A flying bird飞入蜘蛛网时有股冲力，网线坚韧才能捕捉到它，所以选 tough。本句中的 without breaking也指示 tough。
2. B英语中蜘蛛网丝是 spider silk。见第三、第四段分别出现的 silky thread和 spider silk。
3. D 本句说蜘蛛织网的机制和过程，所以选， weave而且，这种蜘蛛就叫 Golden Orb Weaver。
4. C从上下文判断， along之后接的是 the dragline，其代词应为 it。
5. D 本句说 Golden Orb Weaver与某些种类的蜘蛛不同，它不用每天织新网，只要网不破，就能一直使用下去，有时一用 2年，所以选， reuses。
6. C本句将 Golden Orb Wesver蜘蛛网的牢度和张度与防弹衣材料 Kevlar对比，说明该蜘蛛网坚韧的程度。填入的词应该是 Kevlar的同位语， Kevlar是一种材料，所以选 material。
7. B除了上下文的意思要求填 length之外，本句中的用词 stretch和 longer都指示要用 length。
8. A come后面可接形容词。 come close意为“接近”。 come well，come open，come awake都能搭配，但意思与上下文配不上。
9. C It is no wonder (that)是“不足为奇，十分自然”的意思。只有选 wonder意思才连贯。
10. B从意义上判断， a steady supply是正确的选择。 shipment (运送)、run (运转)或 exchange(交换)的意思与上下文配不上。
11. D 上下文的意思要求用“起作用”这个词，英语 work在本句的词义是“起作用”。
12. C下一句是以 Next开始的。有 next，前面很可能有 first之类表次序的词。
13. A 常识告诉我们，把 dragline silk proteins分泌在 milk里，才容易分离出来，所以，选 meat，lungs或 muscle都是不合常理的。
14. B在 without之后要用 any，一般不用 some。英语不说 without no …， many不能修饰 help。
15. A 本题只能选 as fast as。若选 B、C 或 D，意思与上下文配不上。