fire alarm signalling apparatus

例句：

1. 1. The firealarm system is designed to alert people incase of a fire.
   火灾警报系统设计用来在发生火灾时提醒人们。
2. 2. Thefire alarm signalling apparatus wasinstalled in the school's main hall.
   火灾警报信号装置被安装在学校的主大厅里。
3. 3. The engineers worked tirelesslyto ensure that all fire alarm signallingapparatus were functioning properly.
   工程师们努力不懈地工作，确保所有的火灾警报信号装置都正常工作。