求句型语法分析。Few people ask by what authority ..

Few people ask by what authority the writers of dictionaries and grammars say what they say.
其中 the writers of dictionaries and grammars say what they say.是作什么成分？是不是修饰authority？

Few people ask by what authority the writers of dictionaries and grammars say what they say.
很少有人问词典、语法书的编著者凭什么这样写。

Few people主语 ask谓语动词（ by what authority the writers of dictionaries and grammars say what they say）（括号内是宾语从句）.

（ by what authority 状语the writers 主语of dictionaries and grammars定语 say 谓语what they say宾语从句）

宾语从句里又含有宾语从句！

先还原一下句子：few people ask（that） the writers of dictionaries and grammars say what they say by what authority。这样就一目了然了。主干：few people ask+宾语从句 （ the writers of dictionaries and grammars say what they say by what authority。） 再分析从句的主干： the writers （of dictionaries and grammars 这个是定语）say what they say （by what authority这个是方式状语）。再翻译一下：很少有人问及，那些字典和语法书的作者是以什么样的标准（权威）进行写作的。