1.Why couldn't the average man explain how a telephone works? Because he ...

　　2.According to the passage, what is the great pleasure as ignorance? It is the pleasure of ...

　　3.Why was Socrates famous for wisdom? Because he realized his ... at the age of seventy.

　　The average man who uses a telephone could not explain how a telephone works. He takes for granted the telephone, the railway train, the linotype, the airplane, as our grandfathers took for granted the miracles of the gospels. He neither question nor understand them. It is as though each of us investigated and made his own a tiny circle of facts. Knowledge outside the day's work is regarded by most men as a gewgaw. Still we are constantly in reaction against our ignorance. We rouse ourselves at intervals and speculate. We revel in speculations about anything at all --- about life after death or about such questions as that which is said to have puzzled

　　Aristotle, "Why sneezing from noon to midnight was good, but from night to noon unlucky?" One of the greatest joys known to man is to take such a flight into ignorance in search of the knowledge. The great pleasure of ignorance is, after all, the pleasure of asking questions. The man who has lost this pleasure or exchanged it for the pleasure of dogma, which is the pleasure of answering, is already beginning to stiffen. One envies so inquisitive a man as Jewell, who sat down to the study of physiology in his sixties. Most of us have lost the sense of our ignorance long before that age. We even become vain of our squirrel's hoard of knowledge and regard increasing age itself as a school of omniscience. We forget that Socrates was famed for wisdom not because he was omniscient but because he realized at the age of seventy that he still knew nothing.