1.Where do you think he bought the computer?此句为什么不能用完成时表达:

1.Where do you think he bought the computer?此句为什么不能用完成时表达:
where do you think he has bought the compute?
2.look,i have bought a new computer ,---cool,(where did you but it?)请问括号内的能用现在完成时表达吗?
3.where have you been during the winter holiday ,Millie?where did you go during your stay in Hong Kong?请问这两个句子意思差不多,为什么时态不一样?是因为表达的意思不一样吗?