英语句型结构分析请高手帮我分析一下下面的英语句型,It is widely believed that every word has a correct meaning,that we learn these meanings mainly from teachers and grammarians,and that dictionaries and grammars are the supreme authority in matters of meaning and usage.and that dictionaries and grammars are the supreme authority in matters of meaning and usage.是什么从句,如果是状语从句,请说明是什么状语从句,还有修饰主句中的什么部分,

英语句型结构分析
请高手帮我分析一下下面的英语句型,
It is widely believed that every word has a correct meaning,that we learn these meanings mainly from teachers and grammarians,and that dictionaries and grammars are the supreme authority in matters of meaning and usage.
and that dictionaries and grammars are the supreme authority in matters of meaning and usage.
是什么从句,如果是状语从句,请说明是什么状语从句,还有修饰主句中的什么部分,