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问题 选择题

在无色透明溶液中，能够大量共存的离子组是（　　）

A．I-、ClO-、K+、H+

B．Na+、Cu2+、Cl-、SO42-

C．H+、Ca2+、Cl-、CO32-

D．Na+Cl-NO3-CO32-

答案

A．溶液无色，但ClO-与H+生成弱电解质HClO而不能大量共存，且ClO-与I-发生氧化还原反应，故A错误；

B．Cu2+有颜色，不符合题意，故B错误；

C．CO32-与H+反应生成二氧化碳气体而不能共存，且CO32-与Ca2+反应沉淀，故C错误；

D．四种离子无色，且离子之间不发生任何反应，能大量存在，故D正确．

故选D．

单项选择题

For nearly ten years, the Unified Modeling Language (UML) has been the industry standard for visualizing, specifying, constructing, and documenting the (71) of a software-intensive system. As the (72) standard modeling language, the UML facilitates communication and reduces confusion among project (73) . The recent standardization of UML 2.0 has further extended the language's scope and viability. Its inherent expressiveness allows users to (74) 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 (75) 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.

（74）处填（）。

A．model

B．code

C．test

D．modify
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单项选择题

下列哪一项不是心肌梗死的并发症（）

A.心脏破裂

B.梗死后综合征

C.二尖瓣脱垂

D.室壁瘤

E.主动脉窦瘤破裂
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