请英语高手帮帮忙，关于专四的语法题！请详细说明答案的内容，太感谢了！ --

Question

请英语高手帮帮忙，关于专四的语法题！请详细说明答案的内容，太感谢了！
------， the white mountain goat is an extremely sure-footed animal that escapes from its predators by living in the most rugged, rocky landscapes.
A.Having been rarely seen
B.Rarely to be seen
C.Rarely seen
D.Being rarely seen。答案是B

Answer 1

你好，朋友。答案错了，应该是 Rarely seen.
1 B.Rarely to be seen 强调的是一种“目的”概念，在这里与句子的逻辑不符合，所以是错的。
2 C.Rarely seen是正确的答案，做句子主语 the white mountain goat 前置定语，具体解释就是： The white mountain goat, WHICH IS RARELY SEEN, is an extremely sure-footed - - - .
3 如果是Rare to be seen的话，也是对的，这样就等于：WHICH IS RARE TO BE SEEN.

Answer 2

这个答案应该是C吧。
Rarely seen前面省略了(Though it is) rarely seen...
非谓语动词短语作定语修饰the white mountain goat，故用被动Rarely seen，改成从句可以说
The white mountain goat which is rarely seen...
但是一般非谓语动词短语作定语的位置都在修饰词后。