where have you had lunch?完全正确
对地点提问用 where ,后跟一般疑问句
不明白的再问哟,请及时采纳,多谢!可不可以填where did you have lunch？Where did you have lunch?不行。 是一般过去时，而那个句子用的是现在完成时，现在完成时的一般疑问句将 have 提前到句首所以应该是： Where have you had lunch?