听力文摘：缓慢的生存

Silkworms have been bred over thousands of years to behave quite unlike their caterpillarcousins in the wild.

蚕这种动物已经被人类豢养了上千年，这使得它们的行为远远异于野外的毛毛虫同类们。

That's because people purposely breed silkworms to fit this job description:

因为人类故意培养蚕，使得它们能够适应这样的工作岗位：

WANTED–Superlative silk producers.

诚聘：招优秀的产丝工。      

Benefits include housing, unlimited² food and protection fromall predators³.

福利包括住房、包吃包喝、不受天敌威胁。

Wanderlust greatly discouraged. No opportunity for travel.

不欢迎旅游迷。没有出差机会。

Obviously, what makes a good silk producer in captivity⁴ is very different from what helps a caterpillar¹ survive in the wild.

很明显，造就人工饲养的产丝能手的条件跟让野生毛毛虫在野外生存的能力会非常不同。

Commercial silkworms are dynamos at silk production, andcompared to their wild relatives, rather sluggish⁵ about everything else.

跟它们的野生同类相比，商用蚕在产丝方面是能手，但在其他任何方面的行动都很迟缓。

Outdoors, you've probably seen caterpillars⁶ crawling to find food or hide from birds, butcommercial silkworm caterpillars hardly move.

在户外，你可能见过毛毛虫爬来爬去寻找食物或躲避鸟类，但是商用蚕幼虫很少活动。

For silk production, they're kept on open traysbecause they're content to stay put, as long as they have a steady supply of mulberry leaves.

为了产丝，这些蚕就被放在敞口的匾上，因为只要有充足的桑叶供应，它们就会满足于一动不动地呆着。

Even when they reach the moth⁷ stage, commercial silkworms are surprisingly immobile.

即使商用蚕蜕变成蛾子，它们的活动力也惊人地弱。

Wildmoths fly to evade⁹ predators and to lay their eggs in different areas.

野生的蛾子会到处飞，以躲避天敌并且把卵产在不同的地方。

However, commercial silkworm moths⁸ haven't needed to do these things for thousands of years.

但是，从上千年前开始，商用蚕的蛾子就不用做这些事情了。

They've completelylost the ability to fly, even though they still have wings!

即使它们仍然有翅膀，它们也已对完全丧失了飞行的能力。

Here's another difference.

还有一处不同。

In the wild, moths are often very particular about where they'll lay eggs.

野外的蛾子通常对产卵地点很挑剔。

This ensures that baby caterpillars can chomp¹⁰ their favorite leaves as soon as they hatch.

这可以保证它们的幼虫一孵化就能吃到喜欢吃的树叶。

Commercial silkworm moths have lost that instinct too.

商用蚕的蛾子连这种本能也丧失了。

They'll even lay eggs on a sheet of paper,where it's easy for humans to keep track of them.

它们甚至会在纸张上产卵，对于人类来说可以很方便的找到它们。

1 caterpillar   

n.毛虫，蝴蝶的幼虫

参考例句：

• A butterfly is produced by metamorphosis from a caterpillar.蝴蝶是由毛虫脱胎变成的。
• A caterpillar must pass through the cocoon stage to become a butterfly.毛毛虫必须经过茧的阶段才能变成蝴蝶。

2 unlimited   

adj.无限的，不受控制的，无条件的

参考例句：

• They flew over the unlimited reaches of the Arctic.他们飞过了茫茫无边的北极上空。
• There is no safety in unlimited technological hubris.在技术方面自以为是会很危险。

3 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

4 captivity   

n.囚禁；被俘；束缚

参考例句：

• A zoo is a place where live animals are kept in captivity for the public to see.动物园是圈养动物以供公众观看的场所。
• He was held in captivity for three years.他被囚禁叁年。

5 sluggish   

adj.懒惰的，迟钝的，无精打采的

参考例句：

• This humid heat makes you feel rather sluggish.这种湿热的天气使人感到懒洋洋的。
• Circulation is much more sluggish in the feet than in the hands.脚部的循环比手部的循环缓慢得多。

6 caterpillars   

n.毛虫( caterpillar的名词复数 )；履带

参考例句：

• Caterpillars eat the young leaves of this plant. 毛毛虫吃这种植物的嫩叶。
• Caterpillars change into butterflies or moths. 毛虫能变成蝴蝶或蛾子。 来自辞典例句

7 moth   

n.蛾，蛀虫

参考例句：

• A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
• The sweater is moth-eaten.毛衣让蛀虫咬坏了。

8 moths   

n.蛾( moth的名词复数 )

参考例句：

• The moths have eaten holes in my wool coat. 蛀虫将我的羊毛衫蛀蚀了几个小洞。 来自《简明英汉词典》
• The moths tapped and blurred at the window screen. 飞蛾在窗帘上跳来跳去，弄上了许多污点。 来自《现代英汉综合大词典》

9 evade   

vt.逃避，回避；避开，躲避

参考例句：

• He tried to evade the embarrassing question.他企图回避这令人难堪的问题。
• You are in charge of the job.How could you evade the issue?你是负责人，你怎么能对这个问题不置可否？

10 chomp   

v. （人、动物进食时）大声地咬，嚼得很响

参考例句：

• I lost a tooth while chomping on a French baguette!我啃法棍面包时，崩掉了一颗牙！
• They just chomp on tundra, nap a few hours and feast again.它们只是在苔原上大嚼特嚼，睡上几小时，接着再吃。