打开 2020年7月10日2020年7月10日网课问答题库The Chinese characters such as “lou”, “you”, “zhou”, “chou” at the end of the second, forth, sixth and eighth sentences, are pronounced in ______ and they are all flat tones. 解析: 【解析题】前寒武纪还没有真核生物出现。 【 …