Even though it is at least 20 years we got to know, I can’t forget the scene we were intr

Even though it is at least 20 years we got to know, I can’t forget the scene we were introduced to each other.
A. that , where
B. when, in which
C. since , when
D. since, where

A. that , whereB. when, in whichC. since , when(答案→)D. since, where解析：考查特殊句式和定语从句。第一空是一个特殊句式：It be 一段时间since从句 自从…以来有一段时间了。第二空考查定语从句。we were introduced to each other的结构非常完整，所以应该使用关系副词做状语。句意：即使我们认识至少20年了，我还是无法忘记我们被相互介绍的那一幕。

正好我需要