此句为什么从句?they realise that it is of great value to record and teach them to the younger gene
问题描述：
此句为什么从句?they realise that it is of great value to record and teach them to the younger gene
答
they为主语，realise为谓语。
that引导的后面的整句作为宾语。
（They+realise+something，realise后即为宾语从句）
答
realise 做整个句子谓语,that做形式宾语,后面引导的句子解释that,宾语从句