It was long thought that the late Yanshannian epoch is the transition period from trench-arc system (Andes-type active continental margin) to trench-arc-marginal sea system (Western Pacific-type).是什么意思_It was long thought that the late Yanshannian epoch is the transition period from trench-arc system (Andes-type active continental margin) to trench-arc-marginal sea system (Western Pacific-type).在线翻译_英语_读音_用法_例句