_____this kind of disease can cause great harm to the battle.

问题描述:

_____this kind of disease can cause great harm to the battle.
A.It occurs to where it is B.Occurring whereC.Where does it occur D.Where it occurs
为什么选D?Bn呢?

这是地点状语从句.当这种疾病发生时,会对当地的战役造成巨大的危害 .