I’ll never forget the moment I first met Mary and makes me already feel happy.
A. that; that
B. which; what
C. at which; which
D. when; what
网友回答
A. that; that
B. which; what
(答案→)C. at which; which
D. when; what
解析：两个定语从句同时修饰一个先行词 , 要区别对待。I first met Mary中不缺主语和宾语，用when引导定语从句，在句中作状语，此处可相当于at which；第二个空用which或that引导，在从句中做makes的主语。故答案为C。