一些孩子们把一个动作传感器和一个蜂鸣器结合起来，这样当他们的兄弟进来时，他们发出警报声。

Some kids combine a motion sensor and a buzzer so that the alarm sounds when their brother comes in.

youdao

一些孩子们把一个动作传感器和一个蜂鸣器结合起来，这样当他们的兄弟进来时，他们发出警报声。

Some kids combine a motion sensor and a buzzer so that the alarm sounds when their brother comes in.

youdao