Question

i dont know how many fish there is in the river

I don't know how many fish__in the pool A are thereB there are C is there D there is选什么,

Answer 1

因为在I don't know 后面的宾语从句,所以从句要用陈述语序,B、D可选
因为fish是不可数名词,所以选单数,正确答案D