Father told me fish ___ (sleep) with their eyes open.这一题该填什么?

问题描述:

Father told me fish ___ (sleep) with their eyes open.这一题该填什么?
这里的fish是可数名词吗?是单数还是复数?

sleep
fish 就是可数名词.但是sleep不能改单三,因为fish是一个种类啊!