题目内容
数据模型是数据库系统中用于提供信息表示和操作手段的结构形式。实际数据库系统中所支持的数据模型主要有层次模型、网状模型和 【5】 3种。
查看答案
搜索结果不匹配？点我反馈
更多问题
In sports the sexes are separate. (36) and men do not run or swim in the same races. Women are less strong than men. That (37) is (38) people say. Women are (39) "the weaker sex", or if men want to please them, "the fair sex". But boys and girls are taught (40) schools and universities. There are women (41) are famous prime ministers, scientists and writers. And women live longer than men. (42) European woman can expect (43) until the age of 74; a man only until he is 68. Are women’s bodies really weaker The fastest men can run a mile in (44) 4 minutes. The best women need 5 minutes. Women’s times are al- ways slower than (45) , but some facts are a surprise. Some of the (46) women swimmers today are girls. One of them swam 400 metres (47) 4 minutes and 21.2 seconds when she was only 16. The first "Tartan" in films (48) an Olympic swimmer, Johnny Weissmuller. His fastest 400 meters was 4 minutes and 59. 1 seconds, (49) is 37.9 seconds (50) than a girl 50 years (51) ! This does not mean that women are catching men (52) . Conditions are very different now, and sport is much (53) serious. It is (54) serious that some women are given hormone injections. At the Olympics a doctor has to check (55) the women are really women or not. It seems like that sport has many problems. Life can be very complicated when there are more than two separate sexes. 43().
Ann Curry is a famous news presenter of the NBC News "Today" show. When she was 15 she happened to walk into a bookstore in her hometown and began looking at the books on the shelves. The man behind the counter, Mac McCarley, asked if she’d like a job. She needed to start saving for college, so she said yes.Ann worked after school and during summer vacations, and the job helped pay for her first year of college. During college she would do many other jobs: she served coffee in the student union, was a hotel maid and even made maps for the US Forest Service. But selling books was one of the most satisfying jobs.One day a woman came into the bookstore and asked Ann for books on cancer(癌症). The woman seemed anxious. Ann showed her practically everything they had and found other books they could order. The woman left the store less worried, and Ann has always remembered the pride she felt in having helped her customer.Years later, as a television reporter in Los Angeles, Ann heard about a child who was born with problems with his fingers and his hand. His family could not afford a surgical(外科的) operation, and the boy lived in shame, hiding his hand in his pocket all the time.Ann persuaded her boss to let her do the story. After the story was broadcast, a doctor and a nurse called, offering to perform the surgical operation for free.Ann visited the boy in the recovery room after the operation. The first thing he did was to hold up his repaired hand and say, "Thank you. " What a sweet sense of satisfaction Ann Curry felt!At McCarley’s bookstore, Ann always sensed she was working for the customers, not the store. Today it’s the same. NBC News pays her, but she feels as if she works for the people who watch the programmes, helping them make sense of the world. How did Ann help the child get the operation he needed().
W: Excuse me. Can you help me please I’m a new student and I want to take some English classes.M: So do I.W: Oh! Are you a foreign student, tooM: Yes. I’m Swedish. You’re Spanish, aren’t youW: No. I speak Spanish, but I come from Columbia.M: There is a notice board over there. That may tell us which room we should go to.W: Oh, good idea! "Room 110, New students", we are both new students, rightM: Yes, you’re right... No, wait a minute. What about "Room 290, English Language" Is that the place we should goW: Look, further down, near the bottom... "Room 310, English for Foreign New and Old Students".M: That sounds right.W: I think that’s it.M: OK. Let’s go to Room 310. By the way, my name is Carl, Carl Lindstrom.W: I’m Rose Rose Morello.M: I’m glad to meet you,Rose.W: So am I, Carl. Who are these two speakers().
在线性表的顺序存储中，元素之间的逻辑关系是通过 【2】 决定的；在线性表的链接存储中，元素之间的逻辑关系是通过 【3】 决定的。
微信支付 
支付宝支付