OG12 语法第78题，求教

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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

(0sloth 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

答案选D,有个问题一直存在，就是分词作修饰用的时候，何时用ing，何时用过去分词
之前我的想法是，看此动词与其逻辑主语之间的关系，现在看到这题，又有点迷惑了，以及为何要用have been date，这个动作并未影响到现在啊？
还请各位NN劳烦解答

jarod_elf

SC的理念是选择best的choice，不是找ideal的。也许你觉得D别扭，可是其他语法错误很明显。排除之后只有D了。

主语是fossils，复数，直接排除B，C，E，这三项谓语都是单数。
而A，提取主谓宾就是fossils made it the earliest known mammal ... 。 it 要么无所指，要么强行认为指代sloth也不对。化石让树懒成为最早发现的哺乳动物，逻辑不对。应该是 化石被鉴别有3.4亿年之久 这个意思的主体 使树懒成为这地区最早的哺乳动物。因此，D选项用 making引导伴随状语是正确的。

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thx~~~