shredder       
noun [ C ] uk/ˈʃred.ər/ us/ˈʃred.ɚ/
 粉碎机
a tool or machine that is used for cutting things into very small pieces
  a paper/document/vegetable shredder 碎纸机/文件粉碎机/蔬菜切丝机 
 Much of the documentary evidence against her had been put through the shredder before she was arrested. 她被捕前,许多对她不利的书面证据都被放进了碎纸机。