问题
选择题
—I called you at 4:00 yesterday afternoon, but no one answered.
—Sorry, I ______ with my friends at that time.
A．swim
B．swam
C．will swim
D．was swimming
答案
答案：D
考查时态。根据时间状语yesterday afternoon,可知要用过去时态；再据at that time，可知要用过去进行时态。所以选D。