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自动控制系统的动态性能指标包括对给定输入信号的跟随性能指标和对扰动输入信号的抗扰性能指标，常用的跟随性能指标和抗扰性能指标分别有哪些？

答案

参考答案：

跟随性能指标：上升时间、超调量、峰值时间、调节时间；抗扰性能指标：动态降落、恢复时间

写作题

阅读下面短文，然后按照要求写一篇150词左右的英语短文。

Lots of teenagers are trying to enter a university by coping stories and phrases from the internet to fill out their personal statements in Britain. Personal statements are used to show what can make applicants （申请）different as they outline their interests and reasons for studying a particular course. But it seems that some ideas and words are alike, even the same, thanks to an internet site designed to help those who don’t know what to write about themselves. A study found that nearly 800 applications had personal statements containing phrases taken from three online examples. The study, which involved examining 50,000 personal statements, found that 5% used the material from the internet, most from one free website. Borrowed material was most likely to appear at the end of a statement or where the applicant described the reasons for wanting to study a subject. Almost all applications are now completed online, but the new evidence of Internet temptation（诱惑）follow concern that teenagers are cutting and pasting material for A-level coursework(课程作业). A spokesman said later that he and his partners were looking for ways examine whether people appeared to be copying material.

[写作内容]

　　1．以约30个词概括短文的要点；

　　2．以约120个词表达你对校园中出现作弊现象的看法，并包括如下要点：

　　（1）分析某些学生作弊的原因；

（2）指出作弊引起的不良后果；

（3）号召学生们杜绝作弊现象的发生。

[写作要求]

1.          在作文中可以使用实例或其他论述方法支持你的论点，也可以参照阅读材料的内容，但不得直接引用阅读材料中的句子。

2.          作文中不能出现真实姓名和学校的名称。

[评分标准]

　　概括准确，语言规范，内容合适，篇章连贯。

（请考生在答题卷上作答。）
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单项选择题

按作用于除尘器的外力或作用机理，除尘器可分为（）大类型。

A、4

B、3

C、2

D、5
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