1.The postcard is from my pen pal which I received just now.先行词是物所以用which
2.Have you heard of the boy who won the gold medal in the sports meeting 先行词是人用who
3.The student whose name is Linda is in the reading room.这句中指物主代词用 whose
4.I always remember the days which we spent them together 同1which
5.Can you describe the town where you were born 先行词是地点用where