perforation          
noun uk/ˌpɜː.fərˈeɪ.ʃən/ us/ˈpɝː.fəˈreɪ.ʃən/
 [ C ]孔 
a hole in something
  A tea bag is full of tiny perforations. 茶包上满是小孔。 
  [ C or U ] medical specialized穿透膜(或组织的)孔;在膜(或组织)上穿的孔 
a hole that goes all the way through a membrane or tissue or the act of making a hole like this
  One possible complication of colonoscopy is a perforation through the bowel wall that could require surgery. 结肠镜检查的一个可能的并发症是大肠穿孔,必须靠手术解决。