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问题 单项选择题

IDEF0构成包括______。
①外部项 ②数据流
③数据存储和处理 ④箭头和活动

A) ①②
B) ①②③
C) ①②④
D) ④

答案

参考答案：D

解析： DFD模型由4种元素组成，即外部项(数据源及终点)、数据流、数据存储和处理。而IDEF0模型元素的组成更加简单，只有两种元素组成，即箭头和活动。通过这两种元素可以清楚地描述出一个目标系统将要做什么完成什么功能及处理之间的约束，而进出IDEF0图的箭头究竟从哪儿来、到哪儿去，可在专门的文档中说明，不必表示在IDEF0图中。这使得模型简明，从而更适合对大型复杂的应用问题建模。折以本题的答案为D。

单项选择题

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
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阅读理解

The Healthy Habits Survey shows that only about one third of American seniors have correct habits. Here are some findings and expert advice.

1. How many times did you brush your teeth yesterday?

Finding：A full 33% of seniors brush their teeth only once a day.

Step：Remove the 300 types of bacteria in your mouth each morning with a battery-operated toothbrush.

Brush gently for 2 minutes, at least twice a day.

2. How many times did you wash your hands or bathe yesterday?

Finding：Seniors, on average, bathe fewer than 3 days a week. And nearly 30% wash their hands only 4 times a day----half of the number doctors recommend.

Step：We touch our faces around 3,000 times a day-often inviting germs(病菌)to enter our mouth, nose, and eyes. Use toilet paper to avoid touching the door handle. And, most important, wash your hands often with hot running water and soap for 20 seconds.

3. How often do you think about fighting germs?

Finding：Seniors are not fighting germs as well as they should.

Step：Be aware of germs. Do you know it is not your toilet but your kitchen sponge(海绵)that can carry more germs than anything else? To kill these germs, keep your sponge in the microwave for 10 seconds.

小题1:What is found out American seniors?

A．Most of then have good habits.

B．Nearly 30% of then bathe three days a week.

C．About one third of them brush their teeth only once a day

D．All of then are fighting germs better than expected..小题2:Doctors suggest that people should wash their hands     .

A．eight times a day

B．three times a day

C．four times a day

D．twice a day小题3:Which of the following is true according to the text?

A．We should keep from touching our faces.

B．There are less than 300 types of bacteria in the mouth.

C．A kitchen sponge can carry more germs than a toilet.

D．We should wash our hands before touching a door handle.小题4:The text probably comes from       .

A．a guide book

B．a popular magazine

C．a book review

D．an official document
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