首页 >> 外语培训
托福考试
考试指南 | 考试资讯 | 复习指导 | 备考经验 | 托福机经 | 历年真题 | 模拟试题
您当前的位置: 首页 >> 外语培训 >> 托福考试 >> 复习指导(托福考试)
站内搜索:

托福写作满分作文—Raising Oysters
作者:城市网 来源:城市网学院 更新日期:2013-11-16

  In the oysters were raised in much the same way as dirt farmers raised tomatoes- by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. Next, they ”planted” fertilized oyster eggs, which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat. The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them once more into another body of water to fatten them up.

  Until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people’s needs. But today the delectable seafood is no longer available in abundance. The problem has be#e so serious that some oyster beds have vanished entirely.

  Fortunately, as far back as the early 1900’s marine biologists realized that if new measures were not taken, oysters would be#e extinct or at best a luxury food. So they set up well-equipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when, what, and how to feed the larvae. And they knew little about the predators that attack and eat baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940’s a significant breakthrough was made.

  The marine biologists discovered that by raising the temperature of the water, they could induce oysters to spawn not only in the summer but also in the fall, winter, and spring. Later they developed a technique for feeding the larvae and rearing them to spat. Going still further, they succeeded in breeding new strains that were resistant to diseases, grew faster and larger, and flourished in water of different salinities and temperatures. In addition, the cultivated oysters tasted better!


托福考试考试通关必备网络课程免费试听>>
              新托福网络课程
课程名称 老师 课时 试听 报名 学费 有效期

托福强化口语班

刘志云

20

试听

报名

200元

套餐:6个月

单项:3个月

托福强化阅读班

祁连山

18

试听

报名

200元

托福强化听力班

张 艳

44

试听

报名

200元

托福强化写作班

齐 辙

16

试听

报名

200元

托福基础听说班

薛涵予

25

试听

报名

200元

托福基础阅读班

刘 伟

26

试听

报名

200元

托福基础写作班

刘家玮

20

试听

报名

200元

托福词汇必备班

白 杨

19

试听

报名

200元

网站首页 - 关于我们 - 版权声明 - 广告服务 - 网站地图 - 会员专区 - 客户服务 - 疑难解答 - 联系我们
Copyright© 2010 cn.cityy.cn 城市网 版权所有
中国·城市教育 粤ICP备06023013号