The security cameras and alarm system were alerted and the police immediately came to the house and arrested the intruder who was attempting to break a window when they arrived.
监控摄像头和保安系统立刻发出警报，警方立刻赶到现场，逮捕了这一试图通过打破窗户进入家中的男子。
3
He invented an electronic instrument that gives an alarm when an intruder comes in.