mindmap root((敲打)) tap implies making a light blow usually repeated: ~ on the window to attract a friend's attention. knock implies a firmer blow, sometimes amounting to a pounding or hammering, and a correspondingly louder sound: the messenger ~ed loudly to awaken us. (pound 1、重击to strike or hit heavily，如Patrick pounded the couch with his fists用拳头猛敲长沙发，如pounding on the door嘭嘭捶门 2、快速跳动to beat, throb, or vibrate with a strong regular rhythm，如her heart was pounding她的心怦怦狂跳 3、捣碎碾碎to crush or grind into powder or paste，如pound the cloves with salt把蒜瓣和盐捣碎) rap suggests a smart vigorous striking on a hard surface that produces a sharp quick sound or series of sounds: the chairman ~ped for order.（smart表示聪明时，暗示能胜过常人，这里是形容动作轻快） rap music说唱音乐，快速说唱歌词，也叫快板乐，起源于黑人音乐 trump implies a solid pounding or beating that produces a dull booming sound: heard the ~ing and banging of carpenters working on the floor below. （boom低沉有回响的声音隆隆声a loud, deep, resonant sound，如thunder boomed in the sky空中传来隆隆的雷声,如the guns boomed大炮隆隆作响，如'Stop right there,' boomed the Headmaster”站住”,校长用低沉的声音说，另外表示繁荣成长prosperity and growth，如business is booming商业蓬勃发展，如baby boom生育高峰，特别是美国二战后的生育高峰，如baby boomer) thud places more emphasis on the sound and often implies the result of something falling or striking rather than of something being struck: heard the severed tree limbs ~ as they fell.