There are 36 classes in our school.(对划线部分提问)

There are 36 classes in our school.(对划线部分提问)
划线部分：36
应该是：How many classes are there in your school.没争议
但划线部分是：36 classes 时候
应该是什么呢?是同上 How many classes are there in your school.
还是：What's in your school?
还是：what are there in your school?