偶遇一位素未谋面的同行朋友,一番寒暄之后,朋友着急地发问:“你是1974年左右出生的吧?”?!“你怎么知道的?”莫非我脸上已有了些许沧桑的痕迹……“哈哈,因为你有一口四环素牙。你看,我们可是同一代人呢!”朋友指着她自己那一口发黄的牙齿说。“呵呵,原来是两个‘四环素牙’年代的代言人!” Occasionally encountered a colleague friends never met, some greeting, friends anxiously asked: “You are born around 1974?” ?! “How do you know?” Could it be my face has been a little vicissitudes of life Traces ... “Haha, because you have a tetracycline tooth, and you see, we are the same generation!” Said the friend, pointing to her own yellowed tooth. “Oh, the original is the spokesman of two 'tetracycline teeth'!”