【题目】We will never forget the day _____ the famous professor came to our school.
A.that
B.when
C.which
D./

【答案】B
【解析】句意：我们永远不会忘记，这位著名的教授来我们学校的这一天。_____ the famous professor came to our school. 是一个定语从句，修饰先行词the day，关系词在从句中作时间状语，所以用关系副词when，选B。