【判断题】【消耗次数：1】
There existed a certain doubt among the students as to the necessity of the work.
①
正确
②
错误
参考答案：
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相关题目
【单选题】
Which of the following is the time when students work in groups?
①
When all the students are under the control of the teacher
②
When students work in pairs on an exercise or a task
③
When students work in small group
④
When students are expected to work on their own at their own speed.
【单选题】
Which of the following is the time when students work in a pair?
①
When all the students are under the control of the teacher
②
When students work in pairs on an exercise or a task
③
When students work in small groups
④
When students are expected to work on their own at their own speed.
【单选题】
No sooner _______ than they began to work.
①
they had arrived
②
they would arrive
③
had they arrived
④
would they arrive
【单选题】
Which of the following is the time when students work as a whole class?
①
When all the students are under the control of the teacher
②
When students work in pairs on an exercise or a task
③
When students work in small groups
④
When students are expected to work on their own at their own speed.
【单选题】
_______ , I will help you with your work.
①
If I am possible
②
If it possible
③
If possible
④
Possible
随机题目
【单选题】
位置随动系统的根本任务就是实现执行机构对位置指令（给定量）的准确跟踪，被控制量（输出量）一般是负截的空间位移，当给定量随机变化时，系统能使被控制量准确无误地跟随并复现给定量。
①
正确
②
错误
【单选题】
由于位置随机系统的基本特征体现在位置上，体现在位置给定信号和位置反馈信号及两个综合比较方面，因此可根据这个特征将它划分两个类型，一类是模拟式随动系统，另一类是数字式随机系统。
①
正确
②
错误
【单选题】
系统在<img src="20190822/1566466137139154.jpg" title="1566466137139154.jpg" alt="1566466116(1).jpg"/>作用下的稳态误差<img src="20190822/1566466164558083.jpg" title="1566466164558083.jpg" alt="1566466149(1).jpg"/>，说明 ( )
①
闭环传递函数中有一个积分环节。
②
输入幅值过大；
③
型别<img src="20190822/1566466211986141.jpg" title="1566466211986141.jpg" alt="1566466195(1).jpg"/>；
④
系统不稳定；
【单选题】
下图属于（）。<img src="20190823/1566521307906288.jpg" title="1566521307906288.jpg" alt="1566521277(1).jpg"/>
①
绕线式
②
鼠笼式