报警器

nǐ yǒu yì wù zài gōng chǎng ān zhuāng yān wù bào jǐng qì

你有义务在工厂安装烟雾报警器。

You are obliged to install smoke alarms in the factory.

tā men bǎ yān wù bào jǐng qì ān zhuāng zài tiān huā bǎn shang

他们把烟雾报警器安装在天花板上。

They fitted a smoke alarm to the ceiling.