短语词组短語paleozoic c era 古生代the Paleozoic era 古生代late paleozoic era 晚古生代lower paleozoic era 下古生界Early Paleozoic Era 早古生代North China Late Paleozoic Era 華北晚古生代Upper Proterozonic Subera -Paleozoic Era 晚元古 返回 paleozoic era