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问题 选择题
下列说法正确的是（　　）
A．一个数的最小倍数一定大于它本身
B．两个质数的积一定是合数
C．一个自然数，不是质数，就是合数
答案

A、根据“一个数的因数的个数是有限的，最小是1，最大是它本身，一个数的倍数是无限的，最小是它本身”，所以一个数的最小倍数一定等于它本身；

B、两个质数相乘得到的积，除了1和它本身外，还有这两个质数是它的因数．它有4个因数，所以一定是合数；

C、1是自然数，1既不是质数也不是合数，所以任何一个自然数，不是质数，就是合数的说法是错误的．

故选：B．

单项选择题

The traditional model for systems development was that an IT department used （1） which is a process-centered technique, and consulted users only when their input or approval was needed. Compared with traditional methods, many companies find that JAD allows （2） to participate effectively in the requirements modeling process. When properly used, JAD can result in a more accurate statement of system requirements, a beret understanding of common goals, and a per commitment to the success of the new system. RAD is a （3） technique that speeds up information systems development and produces a functioning information system. While the end product of JAD is a(an) （4）, the end product of RAD is the new information system. The RAD model consists of tour phases. During the （5）, users interact with systems analysts and develop models and prototypes that represent all system processes, outputs, and inputs.

（1）处填（）。

A．object-oriented analysis

B．structured analysis

C．process analysis

D．prototype analysis
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单项选择题 A1/A2型题

下列各项中哪一项不属于应用慢性支气管炎的诊断标准（）

A.每年患病持续3个月以上

B.反复发作的咳嗽、咳痰或喘息

C.连续两年以上

D.有肺气肿的体征

E.除外其他心肺疾患
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