I am very upset and don not know _______ to do when I see this.

题目

I am very upset and don not know _______ to do when I see this.
A what
B which
C why
D how

答案

选 A know 是动词,后面接宾语从句,
why 需要和 the reason 连用 ,how 应该和 to do it 连用
题目要表达的意思是 "不知道做什么" ,所以不用 which .
翻译:当我看见这些的时候,我很沮丧,不知道该做什么.