问题
单项选择题
关系数据模型( )。
A．只能表示实体间的1:1联系
B．只能表示实体间的1:N联系
C．只能表示实体间的M:N联系
D．可以表示实体间的上述3种联系
答案
参考答案：D
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关系数据模型( )。
A．只能表示实体间的1:1联系
B．只能表示实体间的1:N联系
C．只能表示实体间的M:N联系
D．可以表示实体间的上述3种联系
参考答案：D
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| Although I had left school against the advice of my teachers, I had, without telling anyone, tried to 1 my studies in literature at evening classes. It was a tiresome 2 from one end of the city to another and to 3 among adults was uninteresting. I was the youngest in the 4 , so the friendship I knew at school was 5 . I put up with it for a short period. It was 6 long a walk on cold winter's nights and it was hard to put my 7 into Shakespeare with wet shoes and trousers. So I continued writing poetry at home. By chance, I 8 some prizes and awards for literature. A young woman from a 9 company came to the college one day. She told me that I won a national poetry award. I 10 at her in astonishment (吃惊) and disbelief. She wanted to make a short 11 about me, to which I said, "No, I couldn't do that." Not that I had any real 12 . I was just frightened. In the end she 13 me that I should do it the following day. So I did. They made a short film of me reading one of my 14 and I became 15 interested in literature than ever. I 16 what I should do after this, and decided some weeks later that I could not 17 myself spending the rest of my days dealing with machines. So one evening, I hesitatingly (犹豫地) told my parents that I wanted to _ 18 to school. They were greatly surprised and a little afraid, but they did not try to persuade me not to. They wanted to know if I was 19 , and if I knew what it meant and 20 I realized that if I gave up my job training, it would be very difficult to get a good job. But nothing could stop me, and they asked about the matter no further. | ||||
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