V about n
II.2 The 'think' group
These verbs are concerned with thought or feeling, or the expression of thought or feeling. The prepositional phrase indicates the topic of the thought or feeling.
It's a problem that has been known about for years.
For the most part, people think about themselves rather than others.
With most of these verbs, the preposition about is sometimes followed by an '-ing' clause.
He told me he had always dreamed about being a star when he was a kid.
With some of these verbs, particularly know, think, and worry, the preposition about is sometimes followed by a noun group and an '-ing' clause. This pattern is V about n -ing.
I think he still worries about me being the youngest.
In the case of the following verbs, the preposition about is sometimes followed by a wh-clause: agonize, brood, bother, care, cogitate, deliberate, differ, disagree, dither, fret, know, muse, philosophize, ponder, puzzle, ruminate, theorize, think, wonder, worry.
agonize agree bother brood care cogitate daydream deliberate differ disagree dither dream fantasize forget fret fume gloat know muse obsess philosophize ponder puzzle rage ruminate speculate theorize think waffle waver wonder worry
It averages out so that you don't need to dither about when to buy.