英文短篇故事（紐約）519 A "Hello" from Behind

The teacher was walking near school. He heard footsteps behind him. Then he heard a woman say, "Hello. How are you?" He wondered whom she was talking to. Could she have been talking to him? Maybe, but who says hello to the back of someone's head? He figured she was talking to someone on her cell phone. Moments later, the woman repeated the greeting. He wondered some more. Had she redialed a broken connection? Had she dialed another person? Or had she, in fact, been addressing him all along? He turned his head to look. A woman had just turned left up an adjoining sidewalk. She looked like one of his ESL students. But he didn't call out. He waited until he saw her in class again. Then he explained why he had "ignored" her. She understood. She said, "Next time, I'll say hello to the front of your head!"