这句话怎么办?其中which 可不可以用that 替代?
问题描述：
这句话怎么办?其中which 可不可以用that 替代?
Dr.Clark spent three years in the National Library during which time he collected most of the data he needed for his new book.
答
不可以,这属于介词提前的情况
介词后面关系代词的选择只需看先行词是人还是物,人用whom物用which