I ran ____ an old friend of mine the other day when I did some s

I ran ____ an old friend of mine the other day when I did some shopping downtown.
A、after
B、about
C、across
D、over
【正确答案】：C
【题目解析】：ran after 追赶，run about 乱跑 , run across 偶然遇到，run over 碾压过。题意为前几天我在市区购物时碰到了我的一个老朋友。因此选C