问题
选择题
—What ______ when the earthquake happened on May 12th ?
—Er, I was having a geography class in the classroom.
A. are you doing B. did you do C. were you doing D will you do
答案
C
题目分析：考查时态。过去进行时表示在过去的某个时间点或者时间段正在发生的事情。句意：当5.12地震发生的时候，你在做什么？—嗯，我在真正教室里上地理课。故C正确。
点评：过去进行时表示在过去的某个时间点或者时间段正在发生的事情。