He set off the larum by accident.

他不小心触发了警报。

The larum went off in the middle of the night.

警报在半夜响起。

They installed a new larum system in the office.

他们在办公室安装了新的警报系统。

The sudden larum startled everyone in the building.

突然的警报惊动了大楼里的每个人。

The fire department responded quickly to the larum.

消防部门对警报做出了迅速反应。