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问题 单项选择题

某水产养殖水体在施撒有机肥后湖面不断冒出气泡，短期内突然有大量的鱼类死亡，最常见的原因是

A．水的pH值异常

B．水中溶解氧含量过低

C．水中有毒物存在

D．水中致病微生物存在

E．鱼类的营养物质严重缺乏

答案

参考答案：C

多项选择题

小儿便秘诊断要点中，应出现2条以上的症状，包括（）

A.腹胀、腹痛

B.大便干燥坚硬，秘结不通，或虽有便意但排出困难

C.排便时间间隔延长，每周排便少于2次

D.直肠内存在大量粪便团块，或有大量粪便潴留史或有与粪便潴留有关姿势

E.有排便疼痛或费力史
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单项选择题 共用题干题

A system's architecture is a representation of a system in which there is a mapping of (1)  onto hardware and software components, a mapping of the (2) onto the hardware architecture, and a concem for the human interaction with these components. That is, system architecture is concerned with a total system, including hardware, software, and humans. Software architectural structures can be divided into three major categories, depending on the broad nature of the elements they show.1) (3) embody decisions as a set of code or data units that have to be constructed or procured. 2) (4) embody decisions as to how the system is to be structured as set of elements that have runtime behavior and interactions. 3) (5) embody decisions as to how the system will relate to nonsoftware structures in its environment (such as CPUs, file systems, networks, development teams, etc. ).

空白（4）处应选择（）

A.Decompostion structures

B.Layer structures

C.Implementation structures

D.Component-and-connector structures
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