问题
单项选择题
下列要素中，不属于DFD的是 (17) 。当使用DFD对一个工资系统进行建模时， (18) 可以被认定为外部实体。
A．加工
B．数据流
C．数据存储
D．联系
答案
参考答案：D
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下列要素中，不属于DFD的是 (17) 。当使用DFD对一个工资系统进行建模时， (18) 可以被认定为外部实体。
A．加工
B．数据流
C．数据存储
D．联系
参考答案：D
阅读下面短文, 掌握其大意, 然后从1-10各题所给的四个选项（A、B、C和D）中, 选出最佳选项, 并在答题卡上将该项涂黑。 If you have been dreaming of becoming an astronaut after you grow up, get start now! An astronaut needs a strong body and mind. Shenzhou VI astronauts are able to live upside-down. They do this not just during sleep, but also when eating and going to the toilet. Before they 1 the space, they had lots of practice. Each upside-down training time lasted 20 days. Chinese astronauts aren’t just spaceship 2 but also machine repairers and scientists. They have to know every part of the spaceship and how it works. 3 something goes wrong, they’ve got to know 4 repair it. Also they do scientific experiments in space. Shenzhou VI astronauts know how to live in 5 . They took a knife, a gun and some dye with them into space. If they land in forests, the knife and gun can 6 them from wild animals. If they 7 the sea, the dye can color the seawater around them yellow. This can drive 8 sea animals away. Astronauts must have strong 9 . They can’t get a headache and be sick. With many things to 10 , they’ve got no time for sickness. Do you still have a long, long way to go?
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