儿科护理学的研究范围包括A．儿童保健 B．疾病预防 C．小儿营养喂养 D．小儿生长发

某校化学兴趣小组同学在学习了催化剂的知识后，想探究氧化铁能否在过氧化氢溶液分解反应中起到催化作用．请你一起参与他们的探究过程，并填写下列空白．

【问题】Fe₂O₃能不能做过氧化氢溶液分解反应的催化剂呢？

【猜想】Fe₂O₃能做过氧化氢溶液分解反应的催化剂．

【实验验证】

	实验步骤	实验现象	实验结论
实验一	在试管中加入少量的H2O2溶液，然后将带火星的木条伸入试管中	木条不复燃	常温下H2O2溶液分解速率非常缓慢，放出很少量氧气，因此木条不能复燃．
实验二	在装有H2O2溶液的试管中加入少量的Fe2O3，然后将带火星的木条伸入试管中	______	______

【结论】Fe₂O₃能加快过氧化氢溶液的分解速率，故Fe₂O₃能作过氧化氢溶液分解反应的催化剂．

【讨论与反思】经过讨论，有的同学认为只有上述两个实验，不能证明Fe₂O₃能作过氧化氢溶液分解反应的催化剂，还要补充一个探究实验．

实验三：【实验目的】探究______．

【实验步骤】①准确称量Fe₂O₃（少量）的质量；②重复实验二的步骤；③待反应结束，将试管里的物质进行______，洗涤，干燥，称量；④对比反应前后Fe₂O₃的质量．

【讨论】如果Fe₂O₃在反应前后质量不变，则说明Fe₂O₃能作过氧化氢溶液分解反应的催化剂．但小华认为，要证明猜想，上述三个实验还不足以说明问题，还需要再增加一个探究实验．

实验四：【实验目的】探究______．

For nearly ten years, the Unified Modeling Language (UML) has been the industry standard for visualizing, specifying, constructing, and documenting the (26) of a software-intensive system. As the (27) standard modeling language, the UML facilitates communication and reduces confusion among project (28) The recent standardization of UML 2.0 has further extended the language’s scope and viability.Its inherent expressiveness allows users to
(29) everything from enterprise information systems and distributed Web-based applications to real-time embedded systems. The UML is not limited to modeling software. In fact, it is expressive enough to model (30) systems, such as workflow in the legal system, the structure and behavior of a patient healthcare system, software engineering in aircraft combat systems, and the design of hardware. To understand the UML, you need to form a conceptual model of the language, and this requires learning three major elements: the UML’s basic building blocks, the rules that dictate how those building blocks may be put together, and some common mechanisms that apply throughout the UML.

A．investors

B．developers

C．designers

D．stakeholders

文化产业具有意识形态属性和产业属性，因其产业属性，文化产业首要的是注重经济效益。

移动宽带业务是4G、3G业务统称。

饭店客人投诉的原因有哪些？