【正确答案】 D

【答案解析】原文：M: Lately, I’ve been so forgetful. I can’t seem to remember anything!W: Really? Maybe you should walk to school via a different street. That might jumpstart your brain.M: Why is that?W: Well, sometimes doing regular activities in a slightly different way can help to re-activate old memory pathways in our brain, or even build new ones.Question: What does the woman suggest the man do to strengthen his memory?题目问男士衬衫上的污渍是从哪里来的。对话的最后，男士告诉自己的妈妈，空姐正伸手给坐在自己旁边的男士提供饮料，突然一股湍流,空姐将饮料洒到了自己身上。由此可见，男士的衬衫是在飞机上弄脏的，故选D