1. 這種題目沒有太大意義.
2. 按照定語從句的語法來說：當先行詞詞被the very, the only,the same,the last修飾時,關系代詞最好用that. 如：
1) This is the very good dictionary that I want to buy.
2) After the fire in his house, the old car is the only thing that he owned.
3. 但是當先行詞指人時,偶爾也可以用who.
如：Wang Hua is the only person in our school who will attend the meeting.
4. the only person做先行詞時,還是看the only,而且關系代詞的選擇跟其在定語從句中做主語還是做賓語沒有關系.