What are you going to see the docter?后面有see动词了,为什么不用dowhen are you going to see the docter，为什么不是when do you going to see the docter
网友回答
句型是going to do ,但是运用起来,do就要用其他动词替代,这里see替代了do
======以下答案可供参考======
供参考答案1:
这个句子是不是有问题？
what are you going to do？或when are you going to see the doctor？
供参考答案2:
因为问句中的be going to do sth. 是一个固定句型，表示将要做某事。其中的do指代动词（在原句中be going to do的do就是see）。例如I am going to take part in the sports meeting.（我将要参加运动会）