Question

Life in the Clear  Transparent animals let light pass through their bodies the same way light passes through a window．These animals typically live between the surface of the ocean and a depth of about 3,300 feet—as far as most light can reach．Most of them are extremely delicate and can be damaged by a simple touch．Sonke Johnsen,a scientist in biology,says,“These animals live through their life alone．They never touch anything unless they’re eating it,or unless something is eating them．”

And they are as clear as glass．How does an animal become see-through?It’s trickier than you might think．

The objects around you are visible because they interact with light．Light typically travels in a straight line．But some materials slow and scatter(散射)light,bouncing it away from its original path．Others absorb light,stopping it dead in its tracks．Both scattering and absorption make an object look different from other objects around it,so you can see it easily．

But a transparent object doesn’t absorb or scatter light,at least not very much．Light can pass through it without bending or stopping．That means a transparent object doesn’t look very different from the surrounding air or water．You don’t see it—you see the things behind it．

To become transparent,an animal needs to keep its body from absorbing or scattering light．Living materials can stop light because they contain pigments(色素)that absorb specific colors of light．But a transparent animal doesn’t have pigments,so its tissues won’t absorb light．According to Johnsen,avoiding absorption is actually easy．The real challenge is preventing light from scattering．

Animals are built of many different materials—skin,fat,and more—and light moves through each at a different speed．Every time light moves into a material with a new speed,it bends and scatters．Transparent animals use different tricks to fight scattering．Some animals are simply very small or extremely flat．Without much tissue to scatter light,it is easier to be see-through．Others build a large,clear mass of non-living jelly-like(果冻状的)material and spread themselves over it．

Larger transparent animals have the biggest challenge,because they have to make all the different tissues in their bodies slow down light exactly as much as water does．They need to look uniform．But how they’re doing it is still unknown．One thing is clear for these larger animals,staying transparent is an active process．When they die,they turn a non-transparent milky white．

1.According to Paragraph 1,transparent animals   ．

A． stay in groups

B． can be easily damaged

C． appear only in deep ocean

D． are beautiful creatures

2.The underlined word“dead”in Paragraph 3 means   ．

A． silently

B． gradually

C． regularly

D． completely

【小题3One way for an animal to become transparent is to   ．

A． change the direction of light travel

B． gather materials to scatter light

C． avoid the absorption of light

D． grow bigger to stop light

3.The last paragraph tells us that larger transparent animals   ．

A． move more slowly in deep water

B． stay see-through even after death

C． produce more tissues for their survival

D． take effective action to reduce light spreading

Answer

1.B

2.D

3.C

4.D

【解析】

1.根据第一段中的句子Most of them are extremely delicate and can be damaged by a simple touch可知,大多数透明动物特别脆弱,轻轻接触都会对它们造成伤害,故选B。

2.由第三段可知,有些动物可以延缓并散射光线,使光线偏离以前的轨道,另一些动物会吸收光线,使其dead止于以前的轨道上。根据这个逻辑关系dead应为“完全”止于以前的轨道上。

3.根据第五段中的句子To become transparent,an animal needs to keep its body from absorbing or scattering light可知,一个动物想要变得透明就要避免它的身体散射或吸收光线,因此C项是其中的一个方法,即避免吸收光线,故选C。

4.由最后一段可知,对于体形较大的动物来说,保持透明是一个积极的过程,需要减少光线的传播,所以答案为D。