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公共英语考试(PETS)阅读文章 Plankton

2012-1-8 22:27| 发布者: 韵儿| 查看: 312| 评论: 5

摘要: Plankton   Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They dri ...

Plankton

  Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals.

  Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the sea‘s plankton generates more than twice as much.

  Despite its enormous food potential, little effect was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the sea‘s resources loom even more important as a means of feeding an expanding world population.

  No one yet has seriously suggested that "planktonburgers" may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists.

  One type of plankton that seems to have great harvest possibilities is a tiny shrimplike creature called krill. Growing to two or three inches long, krill provide the major food for the great blue whale, the largest animal ever inhabit the Earth. Realizing that this whale may grow to100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily.

浮游生物

  数十亿吨的被称为"浮游生物"的小动物、植物散布在世界的海洋中。这些小的动、植物大多太小而难以被人眼看到。它们随波逐流,为许多较大的动物提供了基本的食物。

  浮游生物曾被描述为生长在大陆陆地上的各种草类的海洋对应物。 这种比喻是恰当的。然而就潜在的食物价值而言,浮游生物远胜于草类。一位科学家曾经估计,世界上的草类每年生产大约 490 亿吨有用的碳水化合物,而海洋里的浮游生物每年生产的碳水化合物多于此数的两倍。

  尽管浮游生物具备巨大的食物潜能,但直到最近人们还很少象种植草类那样付出努力养殖浮游生物。现在,海洋科学家们至少已开始研究这种可能性。全球人口不断扩张,海洋资源作为食品的重要性日益突出。

  现在还没有人认真说过"浮游生物汉堡" 会很快在世界上流行起来。然而,作为一种可能养殖的补充性食物资源,浮游生物正引起了海洋科学家们相当大的兴趣。

  一种似乎具有很大收获可能性的微小的虾状浮游生物被称为鳞虾。鳞虾长至 2~3 英寸长时即成为地球上曾居住过的最大动物蓝鲸的主要食物。成熟的蓝鲸可以达到 100 英尺长,150 吨重,所以每头鲸每天吞食 1 吨多的鳞虾一点也不让人吃惊。

 

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引用 游客 2013-9-27 04:21
First, be sure to hand wash . 90% of the down jacket marked to hand, should not dry clean. Because dry syrup used will affect the warmth, but also make cloth aging. The machine wash and tumble , after being screwed stir easily lead clothes out of shape, affecting the appearance and warmth . Two , 30 ℃ water rinse . Down into the cold water first soak for 20 minutes to allow the full wet down jacket inside and outside , and then the detergent dissolved in 30 ℃ warm water , soak a quarter of an hour after the down jacket , and then gently scrub with a soft brush . Rinse with warm water also is conducive to fully dissolve the detergent , rinse the down jacket more clean . Third, the best to use special detergents. Down the birds down the protein fibers , the use of ordinary soap or detergent cleaning ( but can not use detergent enzyme ) , because it has strong alkaline , so that loss of soft down jacket , elasticity and luster , becomes dry hair hard and aging, shortening the life jacke ...
引用 游客 2013-9-15 07:53
First, be sure to hand wash . 90% of the down jacket marked to hand, should not dry clean. Because dry syrup used will affect the warmth, but also make cloth aging. The machine wash and tumble , after being screwed stir easily lead clothes out of shape, affecting the appearance and warmth . Two , 30 ℃ water rinse . Down into the cold water first soak for 20 minutes to allow the full wet down jacket inside and outside , and then the detergent dissolved in 30 ℃ warm water , soak a quarter of an hour after the down jacket , and then gently scrub with a soft brush . Rinse with warm water also is conducive to fully dissolve the detergent , rinse the down jacket more clean . Third, the best to use special detergents. Down the birds down the protein fibers , the use of ordinary soap or detergent cleaning ( but can not use detergent enzyme ) , because it has strong alkaline , so that loss of soft down jacket , elasticity and luster , becomes dry hair hard and aging, shortening the life jacke ...
引用 游客 2013-9-12 00:47
Due to possible tanning and leather finishing layer when greasing agent and cleaning agent for chemical reactions. For example, leather fatliquoring agent is the anion, and the cleaning agent is positive ions will react to destroy the internal structure of the dermis, the obvious bleaching phenomenon occurs, so that prior to use, first with a cleaning agent in the dermis without obvious place to do tests to see whether the product is suitable, if there bleaching, etc., you should stop using the cleaner. If the leather cleaner can make leather shiny, or without any adverse reaction, then the product is suitable, you can begin to clean it. If a model oil skin leather cleaner - America leather king leather cleaner or leather cleaner, Wang Jie, generally do not have that happen. In the best selection of neutral cleaning detergent, such as detergent. Use a damp cloth dipped in a little kiss wiping rags must be soft. Then wipe with a cloth dampened with water intrusion McNair clean enough. R ...
引用 游客 2013-9-4 12:54
Various parts of shoes of different materials, so a different approach tilt. But no matter what kind of athletic shoes have a point is: shoe cleaning, soaking time generally should not exceed 20 minutes; while genuine leather shoes can not be soaked in water. Washed should choose a cool ventilated place to dry, avoid exposure. Leather categories: water easily deformable material. When there is dirt or dust, use a clean, soft, damp cloth, then wipe the leather care agent maintenance. Suede categories: water easily deformed material. When there is dirt or dust can be removed with a soft brush. After using suede leather care agent, you can protect their character. Mesh categories: neutral detergent, soft hair brushing. Wet cleaning not exposure, or vulnerable to fading or yellowing. Synthetic leather categories: Use a clean, soft, damp cloth to wipe clean. When necessary, scrub with a mild detergent and wipe clean. Process categories: some reflective material used for printing or eagerly  ...
引用 游客 2013-8-27 20:27
Shoes should loosen the laces before using shoehorn: Weekdays careful with the use, maintenance is the first step in the shoes. More damage from the heel shoes began. Therefore, it may use a shoehorn shoes. Long-handled can be prepared at home, and usually is prepared to carry. Also, do not wear shoes when hard squeeze, wear shoes with laces loosen the laces before wearing should develop the habit. Prevent deformation of shoes, stuffed shoe best results. Foot shape, moves, body temperature and moisture, rain and other factors could lead to aliasing of shoes, especially the sweat or been exposed to rain, the child must use a fixed shoe-shaped shoe. As the temperature and moisture will make leather relaxation, surviving when the temperature inside the shoe must be configured. Tang said the master, the general public may not be a good pair of shoes last, he proposed to build processing factories or workshops to buy shoes, generally can according to their own shoe-shaped buy the right shoe ...

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