instantly

When the sensor detects smoke, the fire alarm rings instantly throughout the building.

(Chinese) 当传感器探测到烟雾时，火警警报会立即在整栋建筑内响起。

She recognized the old melody instantly, even though she hadn't heard it for years.

(Chinese) 尽管多年未听，她还是立刻认出了那段古老的旋律。