为什么宇宙飞船用KO2而不是Na2O2?

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• 问下关于这两个句子的语法问题.The author,taking the reader on a chronological journey through her native land,skillfully combining history and legend with fragments of fiction.2 Modern bluegrass songs,telling of love and despair and celebrating mountain beauty,reflect the genre's rural origins.第一句的taking.land,是作为插入语吗?为什么这里用taking开头做动词就错了（答案写的这句话这部分是错误的改成who takes the reader.）而第二句话telling 开头的插入语整句话就是对了的.而且为什么第一句话后半句要用combining而不是combine,这里难道不属于主语+分词的错误码?
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