"Because it is a romantic comedy and you know how it is going to end up, on a certain level the story has to be predictable because you know they are going to end up together."

VOA: standard.2010.04.30

If the temperature drops below a certain level it sends a signal, 'turn on the heat', and that signal stays on until it gets a negative signal to turn off.

如果温度降到一定程度以下时,探测器会发送一个信号,打开加热器,直到加热器再收到关闭的信号,它就会一直开着

耶鲁公开课 - 生物医学工程探索课程节选