__has happend is that in the past three years great changes have taken place in shanghai.答案是what.麻烦分析一下句法结构?

__has happend is that in the past three years great changes have taken place in shanghai.答案是what.麻烦分析一下句法结构?
__has happend is that in the past three years great changes have taken place in shanghai.
答案是what.麻烦分析一下句法结构?

__has happend is that in the past three years great changes have taken place in shanghai.答案是what.麻烦分析一下句法结构?
这是一个主语从句.定义:在复合句中充当主语的句子叫做主语从句.这里WHAT HAS HAPPENS作为主语,意为：“上海在过去三年里发生了巨大的变化,这是有目共睹的”