问题
单项选择题
关系数据库是表的集合，对视图进行查询，本质上就是对从（）中导出的数据进行查询；支持数据库各种操作的软件系统称为（）。
关系数据库是表的集合，对视图进行查询，本质上就是对从（）中导出的数据进行查询。
A．一个或若干个基本表
B．一个或若干个索引文件
C．一个或若干个视图
D．一个视图
答案
参考答案：A
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关系数据库是表的集合，对视图进行查询，本质上就是对从（）中导出的数据进行查询；支持数据库各种操作的软件系统称为（）。
关系数据库是表的集合，对视图进行查询，本质上就是对从（）中导出的数据进行查询。
A．一个或若干个基本表
B．一个或若干个索引文件
C．一个或若干个视图
D．一个视图
参考答案：A
| 任务型阅读。 请认真阅读下列短文，并根据所读内容在文章后表格的空格处里填入最恰当的单词。 注意：每个空格1个单词。 | ||||||||||||||
| Searching for the Truth Collecting and writing news is like researching in history: the best information comes from those who were there at the time. So if we want to study the history of China in the sixth century AD, we look at the writings of the people who lived then. They are called the primary sources because they tell us what it was like to live then. People at a much later date who write about the same events are called the secondary sources. For example, when we read the original writings of Jia Sixie on agriculture, we are reading a primary source; when we read about Jia Sixie in our textbook we are reading a secondary source because the passage was written about him and his ideas many years after he died. When we make news we use primary and secondary sources. We can see this most clearly in TV programmes. As we watch the news on TV, the person presenting the programme in the studio is the secondary source ( because he tells us about the news) and the reporter in Iraq or Washington is the primary source ( because he is telling us about what is actually happening there). Without these reporters acting as primary sources, you would never find out what really happened in a war, earthquake, sports meeting, concert or festival. These reporters explain what is happening so we have a clearer idea of what is going on there. They often take photographers with them who act as primary source by giving pictures of events. In a newspaper the position is different because these two roles are often combined. This means a reporter who investigates a story may be the same person who writes it. If this happens, the reporter is both the primary and the secondary source. But the photographer who works with him/her is still a primary source. One of the reasons that it is important to separate primary and secondary sources is that they help us to decide what is a fact and what is an opinion. A fact is something that everybody agrees has happened. An opinion is somebody's idea of what happened. So facts and opinions are often mixed in any report, whether in a newspaper or on TV. What have you learnt from the above passage?
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