Ted is going to his cousin's house for vacation对 going to his cousin's house提问为什么是what is Ted doing for vacation 不是where is Ted going for vacation
问题描述：
Ted is going to his cousin's house for vacation对 going to his cousin's house提问
为什么是what is Ted doing for vacation 不是where is Ted going for vacation
答
对具体的动作提问，用what.
答
我个人觉得两种都有可能,就看你读"Ted is going to his cousin's house for vacation"这句的时候重音是在哪个词或哪几个词上面.
重音在"going to"的话是强调他假期干嘛,重音在his cousin's house 是强调他去哪
答
如果是对his cousin's house 提问,无疑是用where来提问；
如果是对going to ...提问,则须用what...,因为是在对动作提问；
如果是对vocation提问,则用why,询问去his cousin's house的目的.
希望可以帮到你.