【单选题】PC机处理的音频信号主要是人耳能听得到的音频信号, 它的频率范围是( )。
A.300 Hz~3400Hz
B.20 Hz~20KHz
C.10 Hz~20KHz
D.20 Hz~44KH
【单选题】TCP/IP (71) layer protocols provide services to the application (72) running on a computer. The application layer does not define the application itself, but rather it defines (73) that applications need-like the ability to transfer a file in the case of HTTP. In short,the application layer provides an (74) between software running on a computer and the network itself.The TCP/IP application layer includes a relatively large number of protocols,with HTTP being only one of those.The TCP/IP (75) layer consists of two main protocol options-the TransmissionControl Protocol(TCP)And the UserDatagram Protocol(UDP).
A.hardware
B.software
C.packet
D.equipment
【单选题】单个磁头是以( )方式向盘片的磁性涂层上写入数据的。
A、并行
B、并一串行
C、串行
D、串一并行
【单选题】在关系数据库中,通过( )来表示概念记录之间的关系。
A、外来关键字
B、关键字
C、数据字典
D、元组
【单选题】审核工作产品和结果以保证完成满意度和正式验收是以下哪一工作的组成部分()
A、风险管理。
B、质量控制。
C、变更管理。
D、范围核实。