问题 问答题 简答题

为确保空压机最低运转要求,简述一号线车辆空压机是如何管理的?

答案

参考答案:

空压机操作采用主/辅空压机管理的概念,根据日期的单双日变化进行转换,平衡空压机的工作时间。当2号车的空压机作为主空压机运行时,5号车的空压机作为辅助空压机待命。如果总风缸压力下降到8bar时,那么主空压机启动,补充压力空气。当总风缸压力继续下降到7.5bar时,5号车的辅助空压机也将启动,对总风缸的压力加以补充,此时从7.5bar上升到9bar的过程中,两台空压机同时工作。

阅读理解

阅读理解

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.

单项选择题