加载中…2015年 北京卷 Text C life in the clear
(2017-08-02 16:06:19)
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63.According to
Paragraph 1, transparent animals can be easily
damaged.
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一致的. 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.
64.The
underlined word "dead" in
65.One way for
an animal to become transparent is to avoid the absorption of
light.
66.The last
paragraph tells us that larger transparent animals take
effective action to reduce light spreading.
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 3300 feet-- as far as most light can
reach. Most of them are extremelydelicate 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 sth is eating
them."
And they are as clear as
glass. How does an animal become see-through? It`s trickier than u
might think.
The objects around u are
visible because they interact with light. Light typically travels
in a straight line. But some materials slow and scatter散射 light,
bouncing 反射 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 u 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
animalneeds 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.
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