serpentine          
adjective  literary uk/ˈsɜː.pən.taɪn/ us/ˈsɝː.pən.taɪn/
 像蛇一样卷曲的;蜿蜒的
curving and twisting like a snake
  We followed the serpentine course of the river. 我们沿着弯弯曲曲的河道走。 
  复杂难懂的;曲折的
complicated and difficult to understand
  The film's serpentine plot was difficult to follow. 电影曲折的情节让人难以理解。