问题
选择题
Guess what! I came across my primary school science teacher this morning, ______ I have lost touch for almost 20 years.
A．of which
B．when
C．with whom
D．who
答案
答案：C
题目分析：句意：你猜怎么了，我今天早上遇到了小学科学老师，我和他20年没有联系了。这里是定语从句，先行词是my primary school science teacher，定语从句中使用了词组lose touch with sb.所以缺少介词with和关系代词whom，所以选C。