【单选题】
在晶体三极管放大电路中，晶体三极管最高电位的一端应该是___。
A. PNP型的基极
B. NPN的基极
C. PNP型的发射极
D. NPN的发射极
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相关试题
【单选题】
对于半波整流电路，整流系数为___。
A. 0.45
B. 0.60
C. 0.75
D. 0.9
【单选题】
电池A电动势为2V，内阻为1Ω，电池B电动势为2.5V，内阻为2.5Ω，先后用A、B作电源向同一电阻供电，电流相等，这个电阻阻值R=___。
A. 0.5Ω
B. 1.25Ω
C. 2.5Ω
D. 5Ω
【单选题】
下列___或系统未使用时钟系统提供的标准时钟信号。
A. 通信专业
B. 信号专业
C. AFC专业
D. 视频广告
【单选题】
下列___不属于光纤通信特点。
A. 光纤的可扰性好
B. 光纤不怕高温
C. 光纤不怕电磁干扰
D. 通信串音大，保密性差
【单选题】
___属于光纤常用参数。
A. 衰减常数
B. 辐射
C. 驻波比
D. 频率
【单选题】
___是属于无线设备的。
A. 中继器
B. 天线
C. 发送设备
D. 接收设备
【单选题】
轨旁RCS的基本网络拓扑是___。
A. 总线拓扑
B. 环路拓扑
C. 星型拓扑
D. 串联拓扑
【单选题】
以下工具中___是无线测试的专用工具。
A. 万用表
B. 无线接入点测试盒
C. 防雷测试仪
D. 功率表
【单选题】
检查是否存在旧日志文件并将其删除可排除CSR的___故障。
A. 磁盘空间不足
B. 磁盘空间过小
C. 输入电压异常
D. 连接中断
【单选题】
IP地址是___。
A. 接入Internet的计算机地址编号
B. Internet中网络资源的地理位置
C. Internet中的子网地址
D. 接入Internet的局域网
【单选题】
微机唯一能够直接识别和处理的语言是___。
A. 汇编语言
B. 高级语言
C. 甚高级语言
D. 机器语言
【单选题】
断电会使原存信息丢失的存储器是___。
A. 半导体RAM
B. 硬盘
C. ROM
D. 软盘
【单选题】
硬盘连同驱动器是一种___。
A. 内存储器
B. 外存储器
C. 只读存储器
D. 半导体存储器
【单选题】
在下列存储器中，访问速度最快的是___。
A. 硬盘存储器
B. 软盘存储器
C. 半导体RAM(内存储器)
D. 磁带存储器
【单选题】
主机板上CMOS芯片的主要用途是___。
A. 管理内存与CPU的通讯
B. 增加内存的容量
C. 储存时间、日期、硬盘参数与计算机配置信息
D. 存放基本输入输出系统程序、引导程序和自检程序
【单选题】
使用Cache可以提高计算机运行速度，这是因为___。
A. Cache增大了内存的容量
B.
C. ache扩大了硬盘的容量 C. Cache缩短了CPU的等待时间
D. Cache可以存放程序和数据
【单选题】
将二进制数11011101转化成十进制是___。
A. 220
B. 221
C. 251
D. 321
【单选题】
CGA.EGA和VGA标志着___的不同规格和性能。
A. 打印机
B. 存储器
C. 显示器
D. 硬盘
【单选题】
有关二进制的论述，下面___是错误的。
A. 二进制数只有0和l两个数码
B. 二进制运算逢二进一
C. 二进制数各位上的权分别为0，2，4，…
D. 二进制数只有二位数组成
【单选题】
操作系统的作用是___
A. 把源程序翻译成目标程序
B. 进行数据处理
C. 控制和管理系统资源的使用
D. 实现软硬件的转换
【单选题】
下列选项中，不属于计算机病毒特征的是___。
A. 破坏性
B. 潜伏性
C. 传染性
D. 免疫性
【单选题】
以下操作系统中，不是网络操作系统的是___。
A. MS-DOS
B. Windows 2000
C. Windows NT
D. Windows XP
【单选题】
下列设备组中，___完全属于输入设备的一组。
A. CD-ROM驱动器、键盘、显示器
B. 绘图仪、键盘、鼠标器
C. 键盘、鼠标器、扫描仪
D. 打印机、硬盘、条码阅读器
【单选题】
下列各存储器中，存取速度最快的是___。
A. CD－ROM
B. 内存储器
C. 软盘
D. 硬盘
【单选题】
下列关于软件的叙述中，正确的是___。
A. 计算机软件分为系统软件和应用软件两大类
B. Windows就是广泛使用的应用软件之一
C. 所谓软件就是程序
D. 软件可以随便复制使用，不用购买
【单选题】
安装硬盘的正确步骤为___。
A. 跳线、BIOS设置、分区、格式化
B. 跳线、分区、BIOS设置、格式化
C. 分区、格式化、跳线、BIOS设置
D. BIOS设置、分区、格式化
【单选题】
下列器件中不属于组合逻辑电路的有___ 。
A. 加法器
B. 译码器
C. 编码器
D. 计数器
【单选题】
把电气设备的外壳与零线连接称___。
A. 断电保护
B. 断线保护
C. 接零保护
D. 断相保护
【单选题】
某电阻两端接3V电压时,流过的电流是0．1A，则它的电阻是___Ω。
【单选题】
当电源频率增加后,分别与灯泡串联的R.L.C，3个回路并联,与 ___串联的灯泡亮度增加。
【单选题】
无线电天线的位置放置在列车的每个端头，在各个车厢的顶部区域，每节车厢安装___个天线，它们到彼此之间有一定的距离，而且与车辆的中心线成一定的水平角（斜视角）。
【单选题】
___作为满足大坡度、小半径线路，生命周期综合成本较低，建设速度较快，超安静、高环保的轨道交通系统，正日益成为城市轨道交通系统的理想选择之一。
A. 高速铁路系统
B. 地铁系统
C. 中低速磁悬浮系统
D. 单轨系统
【单选题】
电力牵引区段的轨道电路，应能防护连续或断续的___的干扰。
A. 浪涌电压
B. 不平衡牵引电流
C. 功率
D. 不规律频率
【单选题】
列车___是控制中心ATS系统的功能。
A. 监控和跟踪
B. 观测和监视
C. 观察和观测
D. 监视和追踪
【单选题】
对ATP系统的主要认识是按要求使列车___。
A. 缓冲
B. 减速或制动
C. 加速
D. 控制速度
【单选题】
在基于感应环线通信的移动闭塞系统中，感应环线每___交叉一次。
A. 20m
B. 25m
C. 50m
D. 10m
【单选题】
对于一般投诉，原则上应在___日内处理完毕。
【单选题】
城轨交通最突出的特点是___。
A. 安全性
B. 方便性
C. 迅捷性
D. 准时性
【单选题】
问讯处是乘客的求助中心，其设备应尽量采用___。
A. 高等级化
B. 封闭式
C. 开放式
D. 完全自助式
推荐试题
【单选题】
In the race, it looked as if he would be the first, but then another young man who was close behind him put on speed and ___ by a few seconds.
A. beat him for it
B. beat him to it
C. beat him up
D. beat it to him
【单选题】
It is really helpful to have someone like you that we can ___ and count on during difficult times.
A. lean on
B. get to
C. hang on
D. get by
【单选题】
Women have a greater ability to ___ names with faces than men do, and they are also better at recalling lists.
A. associate
B. compare
C. engage
D. involve
【单选题】
He was always ready to help others and managed to ___ his friends ____being hurt.
A. expose … to
B. confine …to
C. restrict … from
D. shield … from
【单选题】
Older people are less likely to be ___ their negative emotions (情绪) and more likely to focus on the positive.
A. reserved for
B. caught up in
C. beat up to
D. counted on
【单选题】
I don’t have any bandage, so I have to ___ pressure to the wound to keep the bleeding down.
A. apply
B. involve
C. fulfill
D. establish
【单选题】
It is important that whichever candidate (候选人) is picked the loser should accept the defeat ___.
A. in advance
B. with great pride
C. with good grace
D. in large part
【单选题】
___ that new homes cost more than older homes, but that is not true across the country anymore.
A. It used to be
B. It is used to be
C. It used to being
D. It is used to being
【单选题】
The boss ___ his employees to work longer hours as the company is dreadfully short of staff at present.
A. called on
B. signed up
C. cared for
D. set up
【单选题】
The president’s visit and ___ discussions led to a plan that aimed to improve the trade relations between the two countries.
A. emerging
B. subsequent
C. consequent
D. Submerging
【单选题】
The author ___ his general idea mainly through statistics and results obtained from a survey (调查) about auto customer services in the United States.
A. assumes
B. engages
C. illustrates
D. represents
【单选题】
People in this town starved, several buildings were bombed and crime ___ because you had to steal to eat.
A. eroded
B. reflected
C. released
D. soared
【单选题】
Olympic recognition for bodybuilding (健美) remains ___ since some argue that bodybuilding is not a sport because the actual contest does not involve the same sort of efforts as “real” sports.
A. controversial
B. conventional
C. characteristic
D. influential
【单选题】
Tom tried to justify his absence from the meeting by ___ that he had been ill that day.
A. admitting
B. advocating
C. claiming
D. citing
【单选题】
___ the huge financial benefits, biological companies have been rushing to set up laboratories and new research projects.
A. Aware
B. Aware of
C. Not aware
D. Not aware of
【单选题】
Unfortunately, ___ lack of funds, the studies he began just two months ago, had to be ended early.
A. out of
B. in addition to
C. owing to
D. to begin with
【单选题】
With a good command of English, he soon got ___ to working with British people.
A. accustomed
B. consistent
C. relevant
D. responsible
【单选题】
What needs to be ___ here is that language and culture interact, and that understanding of one requires understanding of the other.
A. altered
B. stressed
C. aroused
D. committed
【单选题】
Policies and organizations must be created to meet workers’ hopes, and to ___ new problems that inevitably arise between workers and managers.
A. compromise
B. ensure
C. undermine
D. resolve
【单选题】
To keep the wheels of industry turning, we produce consumer goods in endless quantities, and, in the process, are rapidly ___ our natural resources.
A. ignoring
B. collapsing
C. enduring
D. exhausting
【单选题】
As a person who loves peace, he is committed ___ realizing peace between countries.
A. of
B. about
C. for
D. to
【单选题】
Learning how to use chopsticks is easy for me, ___ learning how to conduct myself at the table is quite difficult.
A. whereas
B. however
C. therefore
D. besides
【单选题】
___ that the patient smokes 50 cigarettes a day, it would be reasonable to assume there is some lung damage.
A. To give
B. Giving
C. Given
D. Having given
【单选题】
Kenyan (肯尼亚的) women tend to vote for those who could provide them ___ the necessary food to live on.
A. of
B. with
C. for
D. about
【单选题】
___ all obstacles and failures, the scientist continued doing his experiments day and night.
A. In spite of
B. In contrast to
C. As a matter of
D. As a result of
【单选题】
I’m willing to ___ that a larger car would have cost more, but I still think we should have bought one.
A. withdraw
B. indicate
C. abandon
D. concede
【单选题】
Manufacturing (制造) companies spend millions of pounds on advertisements, trying to ___ customers that their products are better than those of other companies.
A. confine
B. convince
C. depress
D. reconcile
【单选题】
He is not the right person for the project: he is not very technically minded and ___, he does not have the sense of responsibility.
A. instead
B. yet
C. furthermore
D. nevertheless
【单选题】
Death rates declined in many places, partly because of the ___ in hunger.
A. decrease
B. myth
C. obstacle
D. burden
【单选题】
In deciding whether or not a situation is safe, pilots must be taught to assume that the worst will happen, and then to ___ whether there is a risk or not.
A. absorb
B. apply
C. assess
D. occupy
【单选题】
The worker was not worried as he knew that if he gave up the job, there would be ___ opportunities for him to work somewhere else.
A. formative
B. marginal
C. vigorous
D. numerous
【单选题】
The research shows the region might ___ overheating (经济过热), but the policymakers so far appear to be relatively relaxed about the future of the economy.
A. catch a glimpse of
B. be at risk of
C. take a toll on
D. be free from
【单选题】
Measures have been taken to ensure that no student will have to ___ of college for economic reasons.
A. lay out
B. cancel out
C. drop out
D. stand out
【单选题】
Stress that is not treated can lead to significant medical illnesses, which ___ can lead to greater stress and even depression (抑郁症).
A. after all
B. in turn
C. on the contrary
D. at least
【单选题】
Narcissism (自恋) has its benefits in terms of self-belief and confidence, but it also tends to be ___ risky decision-making.
A. associated with
B. contrasted with
C. reserved for
D. relieved of
【单选题】
When Tom saw his doctor again, she suggested that maybe a more substantial lunch, like a sandwich, might ___ his desire to have snacks in the afternoon.
A. count on
B. cut back on
C. hold on to
D. contribute to
【单选题】
You shouldn’t ___ – let your children make their own decisions.
A. interact
B. abuse
C. startle
D. interfere
【单选题】
This is a huge and difficult project and if you take it up, you ___ many difficulties.
A. like to encounter
B. like encountering
C. are likely to encounter
D. are like to encounter
【单选题】
The ability to live for a long time without water is characteristic ___ the camel.
A. of
B. for
C. about
D. in
【单选题】
Rising sales is a good ___ that this product is well received in the market.
A. response
B. convention
C. indication
D. Influence
