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问题 选择题

由CH3CH2CH2OH制备CH2—CHCH3，所发生的化学反应至少有(　　)

①取代反应　②消去反应　③加聚反应　④酯化反应

⑤还原反应　⑥水解反应

A．①④⑥

B．②③

C．②③⑤

D．②④

答案

答案：B

CH3CH2CH2OHCH3CH=CH2

单项选择题

Object-oriented analysis (OOA) is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is (71) . It determines how the various results are computed by the product and presents this information in the form of a (72) . and associated scenarios. The second is (73) , which determines the classes and their attributes; Then determine the interrelationships and interaction among the classes. The last step is (74) , which determines the actions performed by or to each class or subclass and presents this information in the form of (75) .

（72）处应填（）。

A．collaboration diagram

B．sequence diagram

C．use-case diagram

D．activity diagram
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选择题

设f（x）是定义在R上以6为周期的函数，f（x）在（0，3）内单调递减，且y=f（x）的图象关于直线x=3对称，则下面正确的结论是[ ]

A．f(1.5)＜f(3.5)＜f(6.5)

B．f(3.5)＜f(1.5)＜f(6.5)

C．f(6.5)＜f(3.5)＜f(1.5)

D．f(3.5)＜f(6.5)＜f(1.5)
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