单项选择题

下列关于冗余说法错误的是——
A、冗余存在于实体数据和实体间的冗余联系。
B、冗余数据是指可由基本数据导出得到的数据。
C、冗余的联系则是指可由其他关系联合导出的联系。
D、冗余的存在是绝对的,冗余的存在是不可以被接受的。

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听力原文: Nothing can buy a better night's sleep. Although it sounds silly, it was the first thing that crossed my mind when I awokE.I truly appreciated my happy rest. It was like a gift from heaven. Interesting to think that Bill Gales, or arty rich men you can mention, really couldn't have had a more satisfying and grate night of sleep—the best that money can't buy.That started me thinking of other pleasures that cost nothing or very lime and that are often taken for granted, like a drink of cold water on a hot day when you're really thirsty, or a warm relaxing bath when you're extremely tired or mentally exhausted,Remember your first real kiss—can you put a price tag on that? Or the companionship of a faithful and loving pet, or the clean, fresh smell of mountain air? There's an old song, 'The Best Things in Life Are Free'.Did you ever eat a meal that not only filled your stomach and satisfied all your tastes, but refreshed your soul? Ever spend a winter's evening in the company of good friends?What could be better than listening to your favorite music or watching a good movie? Or sharing the beauty of a sunset with a loved one? These are quite delightful and delicate pleasures. I hope this doesn't sound too ridiculous in today's rough, loud worlD.I hope the new generation can appreciate some of these things.What can be inferred from this speech?A.The speaker enjoys sleeping very much.B.The speaker doesn't like money at all.C.Bill Gates does not know how to enjoy himselF.D.Mental well-being is the most important thing.
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We often hear the 【21】______ 'Bug' while using computers. But what is a bug? In computer science, a bug 【22】______ an error in software or hardwarE.In software, a bug is an error in coding or logic that causes a program to malfunction or to 【23】______ incorrect results. Minor bugs, for example a cursor that does not behave as 【24】______ can be inconvenient or frustrating, but not damaging to 【25】______ . More severe bugs can cause a program to 'hang' ( stop responding to 【26】______ and might 【27】______ the user with no 【28】______ but to restart file program. ), losing whatever 【29】______ work had not been saveD.In 【30】______ case, the programmer must find and correct the error by the 【31】______ known as debugging. Because of the 【32】______ risk to important data, commercial application programs are tested and 【33】______ as completely as possible before releasE.Minor bugs found after the program becomes 【34】______ are corrected in next update; more 【35】______ bugs can sometimes be fixed with special software, called patches, that circumvents or otherwise 【36】______ its effects. In hardware, a bug is a recurring 【37】______ problem that prevents a system or set of 【38】______ from working together properly. The 【39】______ of the term reputedly goes back to the early days of computer at Harvard University was 【40】______ a moth caught between the contacts of a relay in the machinE.【21】A.wordingB.termC.dictionD.insect
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