I will never forget the classmates I studied with.
A. that
B. which
C. whose
D. whom
网友回答
A. that
B. which
C. whose
(答案→)D. whom
解析：考查定语从句。本题的定语从句的先行词是the classmates, whom指代先行词作为介词with的宾语。Which指代的先行词不能是人；whose在定语从句中做定语；that实际上是可以的，但是whom是最佳答案。句意：我永远不会忘记和我一起学习的同学们。故D正确。