As a stranger entered a little country store, he noticed a sign warning, "Danger! Beware of dog!" posted on the glass door. Inside, he noticed a harmless old hound dog asleep on the floor beside the cash register.  "Is that the dog folks are supposed to beware of?" he asked the owner. "Yep, that's him," Came the reply.  The stranger couldn't help but be amused. "That certainly doesn't look like a dangerous dog to me. Why in the world would you post that sign?"  "Because," the owner explained, "Before I posted that sign, people kept tripping over him!"一名陌生人走进一家乡间小商店，看到玻璃门上帖着的一个告示牌上写着，“危险! 小心有狗!”  进去后，他看到一条样子一点都不凶的老狗趴在收款机旁边的地板上睡觉。 “这就是大伙都得留神的那只狗啊？” 陌生人问店主。“是，就是他”，店主回答。 听到这个回答， 陌生人觉得很好笑。“我觉得那条狗一点都不可怕。 你帖那个告示做什么？” “因为，” 店主解释说，“在我帖告示之前， 大伙老被他绊倒。”