大流量采样器采集环境空气样品时，采样口的抽气速度为（）m/s。 ["0.1","0.3","0.5","0.7"]
Langston Hughes was noted for his（） ["true description of urban Blacks in poetry","unconventional portrayal of Harlem","singing of black America","None of the above"]
审判监督程序
留在唱片、录音带上的声频信息和摄在胶卷、录像带上的视频信号统称为（） ["光盘","磁带","声像信息","多媒体"]
科技档案保管期限表的条款部分有下列（）组成。 ["说明","序号","条款名称","保管期限","备注"]
电铲中，由磁放大器和可控硅供给励磁绕组电源的电机都属于（）直流发电机。
