GWD-8-Q34，这题我知道只能选D，我只问D为何用完成时。

像风一样离去

219.(GWD-8-Q34) (GWD-13-28)Fossils of the arm of a sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammal of the Greater Antilles islands.

A.sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammal of

B.sloth, that they found in Puerto Rico in 1991, has been dated at 34 million years old, thus making it the earliest mammal known on

C.sloth that was found in Puerto Rico in 1991, was dated at 34 million years old, making this the earliest known mammal of

D.sloth, found in Puerto Rico in 1991, have been dated at 34 million years old, making the sloth the earliest known mammal on(D)

E.sloth which, found in Puerto Rico in 1991, was dated at 34 million years old, made the sloth the earliest known mammal of


答案毫无疑问是D，根据fossils是复数就可以排除ABCE，但是D用什么完成时啊。
各位NN就不用分析题目了，CD的帖子已经够丰富的了，回答一下时态问题我就感激不尽了。

像风一样离去

我顶！！！

像风一样离去

不要沉啊。。。

yanxihua00

貌似我也不懂，请教啊啊啊

cocoloop

有些句子可用的时态不唯一，不同的时态侧重表达的意思不同。D也可以用过去式，如果单纯谈一个过去的动作，不涉及它对现在的影响时，通常用一般过去式；如果谈一件已经发生的事，不考虑它是什么时候发生的，而主要考虑对现在的影响，则多用现在完成时。在这里，making the sloth the earliest known mammal ...强调发现化石对现在的影响，用完成时较好，不过如果用过去式，在语法上也不能算错。

gwang5

同意楼上。

shallbytwo

have beenxxx：已经有xxx年了。
如果用一般现在时，我觉得没有那么强调。
open to discuss。

yanxihua00

谢谢哈～理解了。，。。。。。

像风一样离去

5楼的解释合理，谢谢了。