题目内容
关系数据库是表的集合，对视图进行查询，本质上就是对从(17)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(18)。
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Brain scans can make the doctors know the differences of patients' responses to danger, thus can cure their anxiety disorder.
A(75) infected computer may lose its data．
Computers are electronic machines for processing data. Data are pieces or items of information that have been properly【B1】so that the machine can work【B2】them. Processing means handling the material that has been presented to the machine in【B3】ways as performing calculations, classifying information, or【B4】comparisons. A computer is made of millions of electronic【B5】that can store the data or switch them through【B6】circuits with different functions at【B7】speeds.
In only a short time, computers have【B8】changed the way in which many kinds of work are done.【B9】, they have created whole new areas of work that did not exist【B10】to their development. We have all heard of computers【B11】the course of rockets, preparing bank statements,【B12】elections, forecasting weather, and so【B13】Computers do many tasks for us that would be【B14】difficult if we did not have them. Computers take routine tasks and do them in a【B15】of the time it would take a man or even a【B16】of men to do them.
Many people imagine that a computer is a very large【B17】machine. Certainly a computer can function in that way,【B18】this is a very restricted view of the nature of a computer. The message of a familiar【B19】is that machines should work, but men should think. This is the basic philosophy of computer science,【B20】in the advanced states of computer technology.
【B1】
A．Three.B．Twenty-four.C．Two hundred.D．Eight.
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