问题补充:
They talked for about an hour of things and persons they remembered in the school.
A. which
B. that
C. who
D. whom
答案:
A. which
(答案→)B. that
C. who
D. whom
解析:句意:他们回忆起了在学校时的人和事,谈了一个小时。此空后面是定语从句,先行词是things and persons,当先行词即有人又有物时,定语从句由that引导。故答案选B。