each的单复数问题

sarahfuzq

我在曼哈顿上看到， each一般是用单数，除了they each 用复数
所以each of them/which应该是单数？

When an active tooth in the shark's jaws is lost or worn down, many spare teeth like in seeminly limitless reserve, each of which are ready to slide into the appropriate position.  为什么是对的？

我选的是
In the shark's jaws, many spare teeth lie in seemingly limitless reserve, each on ready to slide into the appropriate position whenever an active tooth is lost or worn down.

其他选项没有each后面是复数的，但是这个不是一个hard error, 肯定不选的吗？

谢谢

greygray

我查了一下这道题，有说答案是A有说是E
支持E，也就是你的选项。
我觉得你说的对，单复数是个大问题，不可忽略，而且each of which 没有each 的独立主格好，所以选E