A：可以! Where 這個關係副詞所引導的關係子句或形容詞子句原本就是用來修飾先行詞為地點的名詞 (如 room, house, city, country 等等)。不過，若使用 where，就不可再用介系詞 (這裡是 in)；若不用 where，則須有介詞，但介詞可以挪到 which 的前面，使其變成 The house in which Allen lives is the oldest in the community. (艾倫居住的房子是本社區最老舊的)。再者，在這句中，which 亦可用 that (關係代名詞) 來替代，但後面仍須保留介詞，且介詞不可挪到 that 的前面，因為 that 的前面不可有介詞；不過，由於 which 或 that 都是 (介詞的) 受詞，因此均可省略。
綜上所述，問題中的句子總共有五種寫法：
- The house where Allen lives is the oldest in the community.
- The house which Allen lives in is the oldest in the community.
- The house in which Allen lives is the oldest in the community.
- The house that Allen lives in is the oldest in the community.
- The house Allen lives in is the oldest in the community.
茲再舉一例來加深大家對這種關係子句句型的印象 (在此使用另一地點介詞 at)：
- That is the restaurant where I will meet Cindy. (那是我要跟辛蒂會面的餐廳)
- That is the restaurant which I will meet Cindy at.
- That is the restaurant at which I will meet Cindy.
- That is the restaurant that I will meet Cindy at.
- That is the restaurant I will meet Cindy at.
所以，下面的句子都是錯的：
- That is the restaurant which I will meet Cindy. (誤)
- That is the restaurant that I will meet Cindy. (誤)
- That is the restaurant I will meet Cindy. (誤)
至於另一關係副詞 when，則是用來修飾先行詞為時間的名詞 (如 time, day, year, century 等等)。它的用法與 where 雷同，但有兩個地方明顯不同，一是介詞不可以放在子句的末尾 (這與其他關係子句的介詞用法皆不同)，二是 that 可視為關係副詞。例如：
- I’ll never forget the day when I first met my wife. (我永遠不會忘記我和內人初次見面的那一天)
- I’ll never forget the day on which I first met my wife.
- I’ll never forget the day that I first met my wife.
- I’ll never forget the day I first met my wife.
若使用 when，就不可再用介詞 (時刻用 at；日期用 on；月份、季節和年份用 in)；若不用 when，則須有介詞，但介詞只能放在 which 的前面，若不用 which，則介詞要省略，不可放在句末。在 when 所引導的關係子句，我們可以用 that 來代替 when，因而這 that 被視為關係副詞。Which 在這兩種句型中皆是關代。
同樣地，茲再舉一例來加深大家對這種關係子句句型的印象 (在此使用另一時間介詞 in)：
- December is the month when the weather is usually the coldest. (十二月通常是天氣最冷的月份)
- December is the month in which the weather is usually the coldest.
- December is the month that the weather is usually the coldest.
- December is the month the weather is usually the coldest.
所以，下面的句子都是錯的：
- December is the month which the weather is usually the coldest in. (誤)
- December is the month that the weather is usually the coldest in. (誤)
- December is the month the weather is usually the coldest in. (誤)