[单选题]企业存在( )应向属地负有安全生产监督管理职责的管理部门及时报备。
A.一般安全隐患
B.重大安全隐患
C.较大安全隐患
D.安全生产风险

Passage 5 Science, in practice, depends far less on the experiments it prepares than on the preparedness of the minds of the men who watch the experiments. Sir Isaac Newton supposedly discovered gravity through the fall of an apple. Apples had been falling in many places for centuries and thousands of people had seen them fall. But Newton for years had been curious a bout the cause of the orbital motion of the moon and planets. What kept them in place Why didn’t they fall out of the sky The fact that the apple fell down toward the earth and not up into the tree answered the question he had been asking himself about those larger fruits of the heavens, the moon and the planets. How many men would have considered the possibility of an apple falling up into the tree Newton did because he was not trying to predict anything. He was just wondering. His mind was ready for the unpredictable, Unpredicability is part of the essential nature of research. If you don’t have
A. shouldn't replace "scientific method" with imaginative thought
B. shouldn't neglect to speculate on unpredictable things
C. should write more concise reports for technical journals
D. should be confident about their research findings

在软件的开发过程中常用图作为描述工具。如DFD就是面向（）分析方法的描述工具。在一套分层DFD中，如果某一张图中有N个加工（Process），则这张图允许有（）张子图。在一张DFD图中，任意两个加工之间（）。在画分层DFD时，应注意保持（）之间的平衡。DFD中从系统的输入流到系统的输出流的一连串连续变换形成一种信息流，这种信息流可分为（）。