你是一名专业的网络小说翻译专家,请将下列网络小说文本翻译成英文.在这个任务中,你将看到一段来自中文网络小说的句子,需要特别注意句子的动词时态和语态.你的任务是根据上下文，将这段句子翻译成英文,确保保留中文文本的原意,同时正确使用动词时态和虚拟语气.
上下文:还好，这三只幼鸟特别，是被村人养着的。可以说，这样一种符文抵得上人族一部很强的骨书，但凡体内能自然生出符文的生物都绝对不凡。
文本:此原始符文极其稀珍，远胜人类研究的一般骨文，为不传之秘，可称之为宝符。
翻译:
human
Their primordial symbols were extremely rare and precious, far surpassing the normal bone texts that were researched by humans. Because these were secrets that could not be passed on to outsiders, they were known as precious symbols.
agent