Graded and ungraded adjectives
Pattern 23: how ADJ a n cl
The adjective follows how and is followed by a noun group beginning with a, and a finite clause. This pattern is used when asking or reporting questions about the extent of a quality, or when talking about the fact that someone or something has a quality to a great degree.
The leaders still have to work out how big a role the army will play in the process.
I mean, how good a career move can it be?
I know how great a debt we owe to those who went before us.
The sad thing is that people forget how sick a woman she has been.