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.
- sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammal of
- 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
- sloth that was found in Puerto Rico in 1991, was dated at 34 million years old, making this the earliest known mammal of
- sloth, found in Puerto Rico in 1991, have been dated at 34 million years old, making the sloth the earliest known mammal on
- sloth which, found in Puerto Rico in 1991, was dated at 34 million years old, made the sloth the earliest known mammal of
答案是C 我选的的D 我感觉C错了2个地方 1: fossils 谓语动词应该用复数,2: this 指代不清楚。 请高手指教!! |