软件维护是软件运行期的重要任务，下列维护任务中( )是软件维护的最少部分。A．预防性

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Dear Reader,

     Today I am going to ask you to support Wikipedia with a donation.

     Wikipedia is built differently from almost every other top 50 website.We have a small number of paid

staff,just twentythree.Wikipedia content is free to use by anyone for any purpose.Our annual expenses are less than six million dollars.Wikipedia is run by the nonprofit Wikimedia Foundation,which I founded in

2003.

     Wikipedia is driven by a global community of more than 150,000 volunteers-all devoted to sharing

knowledge freely.Over almost eight years,these volunteers  have  contributed  more  than 11 million articles in 265 languages.More than 275 million people come to our website every month to access information,

free of charge and free of advertising.

     But Wikipedia is more than a website.We share a common cause:Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge.That's our commitment.

     Your donation helps us in several ways.Most importantly,you will help us cover the increasing cost of

managing global traffic to one of the most popular websites on the Internet.Funds also help us improve the software that runs Wikipedia-making it easier to search,easier to read,and easier to write for.We are

committed to increasing the free knowledge movement worldwide,by taking on new volunteers,and

building strategic partnerships with institutions of culture and learning.

     Wikipedia is different.It's the largest encyclopedia (百科全书)  in history,written by volunteers.Like a

national park or a school,we don't believe advertising should have a place in Wikipedia.We want to keep it free and strong,but we need the support of thousands of people like you.

                                                                                                                              Thank you,

                                                                                                                            Jimmy Wales

1. What do the second and third paragraphs mainly talk about?

A. Why you should donate to Wikipedia.

B. How much the workers are paid.

C. How Wikipedia is run.

D. How many people contribute to Wikipedia.

2. All the following are the reasons for the need of your donation EXCEPT________.

A. to keep Wikipedia free for people all over the world

B. to update the software that runs Wikipedia

C. to raise the salaries of the staff

D. to pay the cost of running the website

3. What does the underlined word "That" in Paragraph 4 refer to?

A. Free access to all human knowledge.

B. Human knowledge.

C. Every single person.

D. A common cause.

4. Which of the following is TRUE about Wikipedia?

A. It only has 23 workers at present.

B. It will run a national park or a school.

C. It has got much help from other people.

D. It may put some advertisements to earn money.

5. What's the author's purpose of writing this text?

A. To introduce the differences between Wikipedia and other websites.

B. To improve the software that runs Wikipedia.

C. To make Wikipedia more popular.

D. To call on people to donate to Wikipedia.

对于（）凸轮，可将百分表测头对准工件中心进行测量，检测时，可同时测出凸轮曲线所占中心角和升高量H，通过计算得出凸轮的实际导程值。

A.偏置直动圆盘 

B.对心直动圆盘 

C.圆柱端面 

D.圆柱螺旋

建立我国政府预算管理体制的基本原则是( )。

A．统一领导、分级管理、权责结合原则

B．公平与效率原则

C．与政治经济体制相适应原则

D．贯彻党的民族政策原则

* * 期间，人们有（）部革命样板戏可看。

A.2

B.4

C.6

D.8

设A为n阶矩阵，α₁，α₂，…，α_n为n个线性无关的n维向量，证明：r(A)]n

Aα₁，Aα₂，…，Aα_n线性无关．