出处：按学科分类—语言、文字 中国对外翻译出版公司《汉英成语词典》第226页（202字）
形容来去无常，不可捉摸，例他们昼伏夜行，神出鬼没，使敌军疲于奔命。
Resting by day and travelling by night，their elusive appearances and disappear ances kept enemy constantly on the run．