换流阀一般采用（）的绝缘方式。A.空气绝缘 B.油绝缘 C.真空绝缘 D.介质绝缘

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

为了测定液体的电阻率,工业上用一种称为“电导仪”的仪器,其中一个关键部件如图所示.A､B是两片面积为1 cm²的正方形铂片,间距d="1" cm,把它们浸没在待测液体中.若通过两根引线加上一定的电压U="6" V时,测出电流I=1μA,则这种液体的电阻率为多少?

关声音叙述，下列正确的是（）

A.声带振动幅度大，声强大

B.声强大，声音响

C.音调高，声强大

D.声带振动频率决定音调

E.音色指声音个性，因人而异

聚合物干粉的入料形成有几种？

常见于溃疡性结肠炎的征象是（）

A.跳跃征

B.狭颈征

C.充盈缺损

D.间位结肠

E.空回肠换位征