句子分析：Where are you going?

表面上看是一句现在进行时,"你正在去哪里",在这里是用现在进行时态表将来;
也可以理解为"be doing",表示将来时,"要干什么","马上就做什么"比如"I am coming"我就来

要是对动作提问应该是问“你正在干什么”“你将要干什么”，是用what are you doing?/what are you going to do?

是的，进行时用be动词

你正在去哪里？
你要用do是 What are you doing?