编辑点评: 研习GRE作文考试的优秀范文不仅可以学到有用的词汇和句子,更能从中学习逻辑的构建方式和作文框架的结构等内容,这里为大家提供GRE的范文,希望对同学们的备考有所帮助。
The preservation of embryos and juveniles is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as marine animals, they tended to live in environments less subject to erosion. Still, their fossilization required a suite of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack of swift currents and waves to jumble and carry away small bones, and fairly rapid burial. Given these factors, some areas have become a treasury of well-preserved ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The ichthyosaur remains are found in black, bituminous marine shales deposited about 190 million years ago. Over the years, thousands of specimens of marine reptiles, fish and invertebrates have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos. Ichthyosaurs with embryos have been reported from 6 different levels of the shale in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development; their paddles, for example, are already well formed. One specimen is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long.
Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched and quarry operations have been carried out carefully with an awareness of the value of the fossils. But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
职场社交英语口语对话 Lesson 2:此话怎讲?
你是否是职场毒药
职场社交英语口语对话 Lesson 26:她还真像个女超人
职场社交英语口语对话 Lesson 27:她可都是玩真的
职场社交英语口语对话 Lesson 19:我就不拐弯抹角了
职场社交英语口语对话 Lesson 31:哇!有一套!
职场社交英语口语对话 Lesson 6:我可不便宜?
职场社交英语口语对话 Lesson 39:你这个疯婆娘!
职场社交英语口语对话 Lesson 5:我要提供你认股权
职场社交英语口语对话 Lesson 3:你是怎么算薪水的?
职场社交英语口语对话 Lesson 17:她整个人热力四射
职场社交英语口语对话 Lesson 43:一张绿色便条纸
职场"老好人"的生存法则
职场社交英语口语对话 Lesson 1:欢迎来到资讯王
职场社交英语口语对话 Lesson 23:你才不要分心
演讲必备的万能句型
职场社交英语口语对话 Lesson 30:你的便利贴是什么颜色?
职场社交英语口语对话 Lesson 37:我真的搞迷糊了
职场社交英语口语对话 Lesson 21:你真是心狠手辣
职场社交英语口语对话 Lesson 25:这是难关,对吧
职场社交英语口语对话 Lesson 48:你对每个人都了若指掌
职场社交英语口语对话 Lesson 12:这是生意经
职场社交英语口语对话 Lesson 10:万一他就是你那伦巴男孩呢?
酒店各种客房的说法
职场社交英语口语对话 Lesson 33:她疯了不成
职场社交英语口语对话 Lesson 20:我得要有动力
职场社交英语口语对话 Lesson 32:我太紧张了
职场社交英语口语对话 Lesson 40:你看她干的好事
职场社交英语口语对话 Lesson 9:你今天早来了
职场社交英语口语对话 Lesson 13:另一张绿色便条纸
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