问题
选择题
----I called you at 4:00 yesterday afternoon ,but nobody answered.
----Sorry,I____with my friends at that time.
A．swim
B．swam
C．will swim
D．was swimming
答案
答案：D
题目分析：句意：昨天下午我给你打电话了，但是没人接。很抱歉，那时我正在和朋友游泳。at that time是过去进行时的标志词，结合句意，故选D.