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问题 选择题
已知一斜坡的坡比为1：2，斜坡长为15米，则斜坡上最高点离地面的高度为（　　）
A．7.5米B．
15
2
3
米		C．3
5
米		D．6
5
米
答案

由已知得斜坡垂直高度与水平宽度之比为1：2．

设斜坡上最高点离地面的高度（即垂直高度）为x米，则水平宽度为2x米，

由勾股定理得x2+（2x）2=152，

解之得x=3

5
．

故选C．

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(1)of a software-intensive system.As the(2)standard modeling language,the UML facilitates communication and reduces confusion among project(3).The recent standardization of UML 2.0 has further extended the language's scope and viability.Its inherent expressiveness allows users to(4)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 (5)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.

空白（5）处应选择（）

A.non-hardware

B.non-software

C.hardware

D.software
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单项选择题

高炉炉渣中MgO能起脱硫作用，要求MgO含量在（）为好。

A、7～12%

B、12～16%

C、16～20%

D、20%以上
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