(On her way) to the supermarket yesterday morning, Mary (met) an old friend and (stopped talking) with him. for (quite a while).
【正确答案】 C
【答案解析】动词短语用法错误，应改为stopped to talk。stop to do“停下来去干另外一件事”；stop doing“停止正在做的事情”，句中是说玛丽停下来和她的老朋友说话。