短语词组短语progressive offlap 渐进退覆;前进退覆offlap sequence 退覆层序marine offlap 海上退覆offlap p 退复staggered offlap 阶段退覆regressive offlap 退覆simple offlap 简单退覆offlap fault 平移断层offlap slope facies 退覆斜坡相 返回 offlap