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问题 选择题

下列几种运动中，属于平移的有

（1）水平运输带上砖的运动 （2）笔直的高速公路上行使的汽车的运动(忽略车轮的转动) （3）升降机上下做机械运动 （4）足球场上足球的运动 [ ]

A.1种

B.2种

C.3种

D.4种

答案

答案：C

选择题

若a是任意有理数，则下列不等式中一定成立的是（　　）

A．（a+1）2＞0

B．a2+1＞0

C．2a＞a

D．a2＞0
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单项选择题

Extreme Programming (XP) is a discipline of software development with (71) of simplicity, communication，feedback and courage．Successful software development is a team effort-not just the development team，but the larger team consisting of customer, management and developers．XP is a simple process that brings these people together and helps them to succeed together．XP is aimed primarily at object-oriented projects using teams of a dozen or fewer programmers in one location．The principles of XP apply to any (72) project that needs to deliver quality software rapidly and flexibly． An XP project needs a (73) customer to provide guidance．Customers，programmers， managers，are all working (74) to build the system that’s needed．Customers-those who have software that needs to be developed-will learn simple, effective ways to (75) what they need，to be sure that they are getting what they need，and to steer the project to success．

（71）处填（）。

A．importance

B．keys

C．roles

D．values
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