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阅读以下说明，回答问题1-5，将答案填入答题纸对应的解答栏内。 [说明] 某单位在部署计算机网络时采用了一款硬件防火墙，该防火墙带有三个以太网络接口，其网络拓扑如下图所示。 防火墙包过滤规则的默认策略为拒绝，下表中给出了防火墙的包过滤规则。若要求内部所有主机能使用IE浏览器访问外部IP地址202.117.118.23的Web服务器，为表中(1)～(4)空缺处选择正确答案，填写在答题纸的相应位置。 序号策略 源地址 源端口 目的地址 目的端口 协议 方向 1(1) (2) Any202.117.118.23 80 (3) (4)
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阅读以下说明，回答问题1-3。 在图书馆数据库有三个基本表：书目表Cata(书号Cno、书名Cname、作者Cauthor、出版年Cdate、价格Cprice)、学生表Student(学号Sno、姓名Sname、性别Sgender、专业Sdept)和借书历史表Borrow(所借书号Cno、借书者学号Sno、借书日期Bbdate、还书日期Brdate)。 [问题1] 请用SQL语句来建立这三个基本表(请注意数据类型的选择)。
Conversation 1[听力原文]6-8M: When in Rome, do as the Romans do, they say.W: What do the Romans doM: They live in Rome, of course, and go to work by car or bus. But sometimes it takes too long that way because of the traffic jams, so they walk.W: In other words, the Romans do what everyone else does.M：Yes，but they do it differently．Everything is different．W: What do you meanM: Well, the climate is different for a start. I know you hate the rain. It doesn’t rain so much as it does in England. The sun shines more often.W: I envy them for the sun.M: I know. You hate the rain, don’t youW: I certainly do.M: And a Roman really loves life. They always eat spaghetti and drink wine.W: Not always, but they like a good meal. Lots of tourists go to Rome just for food.M: Sure. What’s the relationship between the two persons（）
Passage 3 Fire can help people in many ways. But it can be very dangerous. Fire can heat water, warm houses, give light and cook. But fire can burn things, too. It can bum trees, houses, animals or people. Sometimes big fires can burn forests. Nobody knows for sure how people began to use fire. But there are many interesting stories about the first time a man or a woman started a fire. One story from Australia tells about a man very, very long time ago. He went up to the sun by a rope (绳子) and brought fire down. Today people know how to make a fire with matches (火柴) . Children sometimes like to play with them. But matches can be very dangerous. One match can bum a piece of paper and then it might bum a house. A small fire can become a big fire very fast. Fire kills many people every year. So you must be careful with matches. You should also learn to put out fires. (80) Fires need oxygen(氧气). Without oxygen they will die. Cover a fire with water, sand, or sometimes with your coat. This keeps the air away from a fire and kills it. Be careful with fire, and it will help you. Be careless with fire, and it will bum you. We must be careful with fire, or it________.
阅读以下说明和关系表，回答问题1-6。[说明] 设有三个关系 学生S(学号，姓名，性别，年龄，籍贯) 课程C(课程号，课程名，任课老师，所用教材) 学生成绩SC(学号，课程号，得分) 其中规定各属性定义如下： 学号：SNUM 姓名：SNAME 性别：SEX 年龄：AGE 籍贯：NATIVE 课程号：CNUM 课程名：CNAME 任课老师：TEACHER 所用教材：BOOK 得分：GRADE 试用关系代数表达式表示下列查询语句。 [问题6] 检索选修课程包含学号为2且年龄小于20的学生所修全部课程的课程号。
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