qīng qīng de qiāo mén shēng
nínshìfǒuzàixúnqiú:轻轻轻轻的轻轻的敲门声轻轻 轻轻的 轻轻的敲门声gèngduōjiéguǒ...
yīngwénjièshì:
  1. n.  a rap on the door
  2. n.  a light knock on the door, ie not loud