Question

I hope which it will be sunny tomorrow 这里可以填WHICH吗。为什么。

Answer 1

I hope that it will be sunny tomorrow
这里不用which，这是一个宾语从句，从句中不缺任何成分，只能用that引导宾语从句。
由连接词that引导宾语从句时，that在句中不担任任何成分，在口语或非正式的文体中常被省去，
例如：
He has told me that he will go to Shanghai tomorrow. 他已经告诉我他明天要去上海。

which 基本释义：
pron. 哪/那一个；哪/那一些
adj. 哪一个；哪一些

追问

哪种宾语从句中用which。谢谢

追答

宾语从句
which是一个连接代词,在宾语从句中可以充当主语，宾语或定语。意思是“哪一个，那些”
如：I don't know which bike belongs to my father.
I wonder which is better ,this one or that one?
He asked me which I liked best.
I don't know which book is yours.我不知道那本书是你的
He asked which books were his 他问那些书是他的

Answer 2

不可以
that