第一句先行詞指地點,關系副詞在從句中作地點狀語,所以用where.
第二句先行詞雖然指地點,關系代詞在從句中作visit的賓語,用that.
不一定先行詞指地點、時間或reason時,就用關系副詞when、where、why了,一定要看關系代詞在從句中作的成分,如果關系代詞在從句中作的是主語或賓語,仍然用which或that.比較下列各組句子：
I like to take a vacation in the mountains,which is quiet and beautiful.
I like to take a vacation in the mountains,where there are a lot of plants.
Never will I forget the day which we spent together.
Never will I forget the day when we worked together.
That is the reason that my son gave me for not going to college.
That is the reason why my son decided not to go to college.
希望我能幫助你解疑釋惑.