这些词作为疑问词引导特殊疑问句时用疑问句语序
你举的例子：What time do you get up?How many people are there in the classroom?
当这些词,作为连词引导从句的时候,后面用陈述句语序.
比如：I want to know what time you got up.
How many people there are is not important.
当句子中存在情态动词,be动词或者助动词时,疑问句可以直接将这些动词提前.
比如：How long have you been in Shanghai?句中的have 是助动词,直接提前了.
如果句中只含有实意动词时,需要加助动词did/do,一般过去时用did,一般现在时用do或者does
比如：What time do you get up?
What time did you go home?
How often does he watch TV?
这3个句子分别对应了3种助动词,你参考下.