*Ten years ago, we moved to Banchiao, where is my father’s hometown.
這個句子使用關係子句來修飾前面的名詞,但關係代名詞的選擇卻要看它在關係子句中的角色而定。此處的關係代名詞是作為主詞,單純用來代替 Banchiao(板橋)這個地方名詞,做為關係子句的主詞,是名詞性的用法,所以要用 which。故正確的句子為:
Ten years ago, we moved to Banchiao, which is my father’s hometown.
此外,關係代名詞也可以作為副詞,例如:
If you want to go shopping in this city, [where/in which the price for goods is surprisingly high], I also know some great stores where you can buy inexpensive clothes.
此處的關係代名詞所代替的是 in the city (= in which = where),說明事件發生之處,是副詞性的修飾語:「在」這座城市「裡」,因此要用 where 或 in which。