求助--OG--Fossils of the arm...

lyy_chasedream

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
  

答案：D。看过一些解析后可以通过排除法选出D答案。
on the island，排除ACE；
fossils是复数，BCE的动词用了单数形式，排除；
making而不是made，排除AE。


但还是有疑问：
1.一定是on the island吗？只有这一个固定搭配吗？
2.不理解D答案中为什么是have been dated？


求助各位大神！！求解答！！
谢谢！！

Fiona09

核心词是fossils, 所以用have been dated, 而不是用has been...

on the island和of the island其实都可以搭配，但得看语义，of sth一般是表示一种从属关系，用在这里显然不对

lyy_chasedream

Fiona09 发表于 2017-8-30 12:11
核心词是fossils, 所以用have been dated, 而不是用has been...

on the island和of the island其实都可以 ...

哦哦，on the island的问题明白了，多谢！
我在问题里面可能没有表达清楚，我明白这里应该用have而不是has，但是想问问为什么要用现在完成时？是表达对现在造成影响的意思吗？