Re: 回复

 

应该是 as to = about, "whether..." 做as to (about) 的介词宾语。

as to

 

1 : ²about
▪ I'm at a loss as to how to explain the error. [=I don't know how to explain the error] ▪ There is disagreement as to the causes of the fire. ▪ I remained uncertain as to the value of his suggestions.

 

2 : according to, by
▪ The eggs are graded as to size and color.

 

URL: http://www.learnersdictionary.com/search/as%20to