A. If he always talks about himself. B. If he hides his emotion and does not often get excited. C. If he talks a lot to strangers. D. If when he talks to his friends he shows much emotion. 参考答案:B 答案解析:[分析] 本题测试点为文章细节的掌握。参见文中第二句“沉默寡言的人与陌生人不作过多的交谈,很少流露真情,几乎不激动。”由此可得出在日常生活中我们可用B中的方法判断出一个人内向或外向。故选B。