wham  
exclamation  informal uk/wæm/ us/wæm/
  (SOUND)      
  (表示重击声)砰;嘭
used to suggest the sound of a sudden hit
  The boys in the cartoon were punching each other - wham, zap! 卡通片里的男孩们正在打斗——砰,啪! 
   (SUDDENLY)      
 (表示事情的突然发生)砰;嘭
used to show that something you are describing happened suddenly
  Everything was fine until, wham, the wire snapped. 一切都很好,可突然啪的一声,电线断了。