It should go without saying that the focus of UML is modeling. However, what that means, exactly, can be an open-ended question. （）is a means to capture ideas, relationships, decisions, and requirements in a well-defined notation that can be applied to many different domains. Modeling not only means different things to different people, but also it can use different pieces of UML depending on what you are trying to convey. In general, a UML model is made up of one or more（）. A diagram graphically represents things, and the relationships between these things. These（）can be representations of real-world objects, pure software constructs, or a description of the behavior of some other objects. It is common for an individual thing to show up on multiple diagrams; each diagram represents a particular interest, or view, of the thing being modeled. UML 2.0 divides diagrams into two categories: structural diagrams and behavioral diagrams.（）are used to capture the physical organization of the things in your system, i.e., how one object relates to another.（）focus on the behavior of elements in a system. For example, you can use behavioral diagrams to capture requirements, operations, and internal state changes for elements.

（）focus on the behavior of elements in a system.

A．Activity diagrams

B．Use-case diagrams

C．Structural diagrams

D．Behavioral diagrams

患者，女，35岁，活动后心悸、气促3年，加重伴双下肢水肿半年。查体：消瘦，贫血面容，双下肢水肿，心界不大，心音弱，未闻及杂音，腹部隆起，移动性浊音阳性，胸片提示：心影周围可见钙化影。最有可能的诊断是

A．二尖瓣狭窄
B．左房黏液瘤
C．二尖瓣关闭不全
D．慢性缩窄性心包炎
E．以上都不是