Those units or components give visual or aural warning of conditions in unrelated systems. 这些单元或组件在不相关的系统中发出视觉或听觉警告。
A.The parts or components provide visual or auditory warnings in unconcerned systems. B.Those assemblies or components provide visual or aural warning in irrelevant systems C.Visual or aural warning of conditions in irrelevant systems are supplied by those units or components.正确答案C
