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| 文章出处：学生大考试站 发布时间：2005-10-12 |
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A unusual ways to advertise products
B types of payment plans for service
C theories about how products affect different levels of society
D how certain elements of a price “ package” influence its market value Passage 3
In the past 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 , and 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 in other waters to speed up their growth, and then transplanted them once more into another body of water to fatten t hem 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 become so serious that some oyster bed s have vanished entirely.
Fortunately, as far back as the early 1900’s mar
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