Question

At about the same time,doctor began to understand _____ together.

what went dirt and disease
that dirt and disease went
填哪个 为什么 ?
再翻译一下 谢谢。。。

Answer 1

解答：
At about the same time,doctor began to understand that dirt and disease went together.
几乎同时，医生开始意识到污物和疾病混在了一起。
解释：

that引导的宾语从句做understand的宾语。
what went dirt and disease本身语序就不对。
希望能帮到你！