—I can never forget the day we spent together in the summer camp．
—Well, especially the day it suddenly began to rain in the middle of the night．
A. when; when
B. which; when
C. what; that
D. on which; when
网友回答
A. when; when
(答案→)B. which; when
C. what; that
D. on which; when
解析：考查定语从句。本题两空都引导定语从句，第一空的连词在从句中做spend的宾语，用that/which；第二空的连词在从句中做状语，用when。