以in which开头的特殊疑问句回答时还用加介词in吗

问题描述:

以in which开头的特殊疑问句回答时还用加介词in吗
就是in which啊
原句:in which country do people...

where可用于句首,in which不能.
where do you live?
this is the house in which i have lived 14 years.