What’s your middle school?你哪个中学的?怎么说呢!

What’s your middle school?你哪个中学的?怎么说呢!
What’s your middle school?
你哪个中学的?怎么说呢!

What’s your middle school?你哪个中学的?怎么说呢!
Where are you milldle shool

你那样说是对的啊

对的

Which school are you in?

quite right.
最简单的问法是：
which school?
当然是口语化的

对