The other day I was talking to a stranger on the bus; he told me that he had a good 1 in Chicago and he wondered if, by any chance, I 2 to know him . For a moment, I thought he might be 3 , but I could tell from the expression on his face that he was not. He was 4. I felt like saying that it was ridiculous (可笑的) to think that out of all the millions of people in Chicago I could possibly have ever bumped into his friend. But, 5, I just smiled and reminded him that Chicago was a very 6 city. He nodded, and I thought he was going to be content to drop the subject and talk about something else. But I was wrong. He was silent for a few minutes, and then he 7 to tell me all about his friend.

    His friend's main 8 in life seemed to be tennis. He was an excellent tennis player, and he even had his own tennis court（网球场）. There were a lot of people with swimming 9, yet there were only two people with private tennis court; his friend in Chicago was one of them. I told him that I knew several 10 like that, including my brother, who was doctor in California. He 11 that maybe there were more private courts in the country, than he realized but he did not know of any others. Then he asked me 12 my brother lived in California. When I said Sacramento, he said that was a coincidence(巧合) 13 his Chicago friend spent the summer in Sacramento last year and he lived next door to a 14 who had a tennis court in his backyard. I said I felt that really was a coincidence because my next-door neighbour had gone to Sacramento last summer and had hired the house next to my brother's house. For a moment, we stared at each other, but we did not say anything.

    “Would your friend's name happen（碰巧） to be Roland Kirkwood?” I asked finally. He laughed and said,“Yes. Would your brother's name happen to be Dr Rey Hunter?” It was my 15 to laugh. “Yes,” I replied.

    He was the baby with no name. Found and taken from the north Atlantic 6 days after the sinking of the Titanic in 1912, his tiny body so moved the salvage (救援) workers that they called him “our baby.” In their home port of Halifax, Nova Scotia, people collected money for a headstone in front of the baby's grave (墓), carved with the words: “To the memory of an unknown child.” He has rested there ever since.

    But history has a way of uncovering its secrets. On Nov. 5, this year, three members of a family from Finland arrived at Halifax and laid fresh flowers at the grave. “This is our baby,” says Magda Schleifer, 68, a banker. She grew up hearing stories about a great-aunt named Maria Panula,42, who had sailed on the Titanic for America to be reunited with her husband. According to the information Mrs. Schleifer had gathered, Panula gave up her seat on a lifeboat to search for her five children -- including a 13-month-old boy named Eino from whom she had become separated during the final minutes of the crossing. "We thought they were all lost in the sea," says Schleifer.

    Now, using teeth and bone pieces taken from the baby's grave, scientists have compared the DNA from the Unknown Child with those collected from members of five families who lost relatives on the Titanic and never recovered the bodies. The result of the test points only to one possible person: young Eino. Now, the family sees no need for a new grave. "He belongs to the people of Halifax," says Schleifer, "They've taken care of him for 90 years."

    Adapted from People, November 25, 2002

光的折射定律：光折射时，折射光线、入射光线、法线在____内；折射光线和入射光线分别位于法线____。光从空气斜射到水或玻璃表面时，折射光线向法线____，折射角____入射角。光垂直射到水或玻璃表面中，在水或玻璃中传播方向____。