问题补充：
There are 2,472 kinds of animals and plants,among which 24 animals and 17 plants are seldom seen by us.其中which引导的是不是非限制性定语从句?在句中充当什么成分?
答案：
AMONG 和WHICH共同引导一个非限制性定语从句,
WHICH代指前面的“2,472 kinds of animals and plants”.AMONG WHICH在从句中做状语.
把定语从句还原则为“among 2,472 kinds of animals and plants ,24 animals and 17 plants are seldom seen by us ”
======以下答案可供参考======
供参考答案1:
是限制性定语从句吧？充当主语。。。。
