现在分词&过去分词求解 谢谢谢谢！！

abjure

是啊，这题的理解和你一样。

AmyGMAT

啊 哈哈 误会你意思了...

AmyGMAT

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


这里OG对it指代不清的解释是：Because sloth is the object of a preposition and not the subject of the sentence，there is no reason antecedent for the pronoun it
这个和上面那个解释是如出一辙的，那么是不是就可以这么理解：在介词后的名词不能充当先行词？？

SAGA5

没有绝对的介词后名词不做先行词
这道题里 因为SLOTH在语法结构中的地位很低（不是主语也不是宾语的地位，而是某种修饰的意味）远比不上主语名词 所以相比起来没有理由不指主语而指SLOTH