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问题 选择题

已知元素X的原子序数为17，则元素X在周期表中的周期序数为（ ）

A  3          B  5         C  4          D  6

答案

答案：A

原子序数为17的元素是氯元素，位于第三周期第ⅦA，答案是A。

填空题

在有防火防爆要求的环境中，一般宜采取自然通风，当自然通风不能满足要求时应采取（）。
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单项选择题

During the past years, intelligent technology has evolved (116) three generations. The first was characterized by tools such as prolog and OPS. prolog is a simple backward-chaining environment, and OPS is a simple forward-chaining environment. This led to the second generation of knowledge-engineering environments. Its goal was to model, prototype and construct (117) systems.
All three generations were oriented toward generic (118) and represented generalized implementation environments for the construction of expert systems. knowledge bases and AI applications.
Some of the solution-oriented products are also seamlessly integrated with generic knowledge-engineering environments, permitting end users to add (119) rules and objects, as well as predefined knowledge-based logic to address problems in manufacturing simulation.
Marketplace orientation is rapidly (120) toward solution-oriented intelligent product environments. the fourth generation represents a new line of thinking and ’ develop-merit by commercial fu-ms. will reduce the cost risk and development time associated with problem solving.

A．custom

B．knowledge

C．through

D．problem solving
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