一个活动是指状态机中一种可中断的计算，中断处理后仍可继续；而一个动作是指不可中断的原子计算，它可导致状态的改变或导致一个值的返回。因此活动和动作之间没有任何关系。
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在UML可模型化的4种事件中，“信号”是一种异步事件，而“调用”一般是同步事件。
A. 对
B. 错
UML表达模型元素之间关系的4个术语都体现了结构抽象的原理。
A. 对
B. 错
How do data and information differ?
A. data is a body of facts in a format suitable for decision making, while information is simply facts
B. they are the same
C. data is simply facts; information is a body of facts in a format suitable for decision making
D. data is associated with decision support systems; information is associated with ERP systems
What has emerged as the measuring stock for logistics information technology in the 21st century?
A. the Internet
B. electronic data interchange
C. wireless communication
D. enterprise resource planning systems
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