关于as to 的用法Rooney had no doubts as to where the winning goal

关于as to 的用法
Rooney had no doubts as to where the winning goal belonged in the context of his career
我觉得as to 是作为一个关系副词,后面接where所表示的状语从句
后面我在百度上找到一些相关的用法.下面详细说明,希望可以提高我们
用于提出问题：as to必须位于句中,前面出现的大都是表达某种心理活动的动词,形容词或名词,其后引接出wh-clause或who-to-v结构,表示“在……的问题上”、“就……问题来讲”,所引出的问题都有很强的针对性.但有人认为这里的罄to显得多余,去之亦通.所以,有时也不必译出.例如：
①There is some doubt as to whether the proposal is practicable．
②I enquired of the clerk as to which documents were needed．