TPO5-3 The Cambrian Explosion

At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.

At one time, the animals were assigned to animal groups,but most paleontologists now agree that all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.

all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.

all Tommotian fossils represent unique body forms,leaving no descendants in modern animal groups.

在一个时间上，化石上的动物被指派给现代动物群体，但是大多数古生物学家认为“所有的Tommotian化石表现了一个独一无二的身体组成，这些化石在当代动物群体中没有留存后代。

逻辑：化石指派给现代动物，但是学者认为没有后代。

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The animals found in the Tommotian fossil bed were once thought to belong to a variety of modern animal groups, but now they are thought to have descended from a single group.

在化石上找到的动物曾经被认为属于某一个现代动物群体，但是现在它们被认为有一个单支的后代。------错误，不是有一个单只，而是没有后代。

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Animals in the Tommotian fossil beds were initially assigned to modern animal groups but are now thought to belong to groups that emerged and died out during the Cambrian period.

在化石上找到的动物曾经被认为属于某一个现代动物群体，但是现在它们被认为属于一个群体，该群体曾经出现然后消失了

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Though at first they thought otherwise, paleontologists now agree that the animals in the Tommotian have body forms from which modern animals have descended.

虽然刚开始想法是相反的，但是古生物学家现在认为：化石上的动物有这样一个身体构成，当代动物从这个身体构成传承下来。------错误，当代动物不是化石生物的后代。

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It is unclear whether the Tommotian fossils from the early Cambrian period represent unique body forms or whether they should be assigned to various modern animal groups.

“化石动物是否代表独特的身体构成”或者“是否这些化石动物被指派给当代动物群”是不清楚的。------错误，化石动物没有当代动物群的后代。