搜题请搜索小程序“爱下问搜题”
问题 多项选择题

在自动控制系统中，定值系统是把给定值X（S）固定不变，把干扰作为系统的输入量，那么项目叙述正确的是（）。

A、系统只考虑偏差变量E（S）对干扰量F（S）的响应

B、系统只考虑输出变量Y（S）对干扰量F（S）的响应

C、系统只考虑干扰量F（S）对于偏差变量E（S）影响

D、系统只考虑干扰量F（S）对于被控变量Y（S）影响

答案

参考答案：B, D

选择题

专制主义中央集权制度创立于秦朝，关于这项制度说法错误的是  [ ]

A、国家的法律、政策，都决定于皇帝一个人的意志

B、 “主独制于天下而无所制也”成为中国古代的政治定律

C、历代官僚体制虽有变化，但都以维护王权、服务于皇帝为基本准则

D、皇帝的决策往往要得到群臣的一致意见
查看答案
单项选择题

The worst thing about television and radio is that they entertain us, saving us the trouble of entertaining ourselves.

The author’s attitude toward karaoke is ______.
A. negative B. positive C. neutral D. indifferent

A hundred years ago, before all these devices were invented, if a person wanted to entertain himself with a song or a piece of music, he would have to do the singing himself or pick up a violin and play it. Now, all he has to do is turn on the radio or TV. As a result, singing and music have declined.
Italians used to sing all the time. Now, they only do it in Hollywood movies, Indian movies are mostly a series of songs and dances trapped around silly stories. As a result, they don’t do much singing in Indian villages anymore. Indeed, ever since radio first came to life, there has been a terrible decline in amateur (业余的) singing throughout the world.
There are two reasons for this sad decline. One, human beings are astonishingly lazy. Put a lift in a building, and people would rather take it than climb even two flights of steps. Similarly, invent a machine that sings, and people would rather let the machine sing than sing themselves. The other reason is that people are easily embarrassed. When there is a famous, talented musician readily available by pushing a button, which amateur violinist or pianist would want to try to entertain family or friends by himself
These earnest reflections came to me recently when two CDs arrived in the mail. They are historic recordings of famous writers reading their own works. It was thrilling to hear the voices from a long dead past in the late 19th century. But today, reading out loud anything is no longer common. Today, we sing songs to our children until they are about two, we read simple books to them till they are about five, and once they have learnt to read themselves, we become deaf. We’re alive only to the sound of the TV and the stereo (立体声音响).
I count myself extremely lucky to have been born before TV became so common: I was about six before TV appeared. To keep us entertained my mother had to do a good deal of singing and tell us endless tales. It was the same in many other homes. People spoke a language; they sang it, they recited it; it was something they could feel.
Professional actors’ performance is extraordinarily revealing. But I still prefer my own reading, because it’s mine. For the same reason, people find karaoke (卡拉OK) liberating. It is almost the only electronic thing that gives them back their own voice. Even if their voices are hopelessly out of tune, at least it is meaningful self-entertainment.
查看答案