ADJ as to wh
The 'uncertain' group
These adjectives indicate that someone is certain or, more commonly, uncertain about a situation, or that they know or do not know about it.
Scientists were not at all clear as to what was going on in the Earth's crust.
A trifle uncertain as to what to do for the best, she decided to go in.
The preposition as to is sometimes followed by a noun group.
certain clear clueless confused doubtful hazy ignorant informed sure unaware uncertain unclear undecided unsure vague
The two species of lemur belong to a distinct family, but zoologists are still uncertain as to their closest relatives.
Many buyers and sellers may be a little unsure as to the condition of the property market.