How many hours is it going to take Stephanie to get to Los Angeles?

问题描述:

How many hours is it going to take Stephanie to get to Los Angeles?
Could you tell me what kind structure this sentence is What is the "it" instead?

句型是it takes/ will take sb some time to do sth
变成问句就是how many hours will it take sb to do sth?
it代替后面的to do sth