怎样判断FA断路器的状态？机构箱内分合指示器能否说明断路器的实际位置？
在多进制调制系统中，当Rb相同时，增加进制数M，或RB相同时，增加进制数M，对频带利用率ηb的影响分别是（）。 ["提高，提高","减小，减小","提高，减小","减小，提高"]
During the PSC inspection, under the provisions of SOLAS 74, which one may not be regarded as clear grounds for ships’ detainment?（） ["failure of the proper operation of the main steering gear","failure of the proper operation of electrical installations","leakage of domestic water pump","insulation of exhaust pipes in engine room contaminated by oil"]
FA型断路器分闸闭锁有哪些原因？
下列选项中不属于物防设施的是（）。 ["A.营业场所出入口安装的防盗安全门","B.现金柜台上方安装的防弹玻璃","C.营业区与客户区间安装的防尾随联动门","D.出入口安装的监控装置"]
DOS组成中，负责与用户直接交互的是（）。
