The small donation she made was just a drop in the bucket for the charity's fundraising goal.
The amount of money he donated was just a drop in the ocean compared to what was needed.
Guessing the answer was just a shot in the dark, but somehow he got it right.
Finding her lost earring in the park was like looking for a needle in a haystack.
His story may have had a grain of truth, but most of it was exaggerated.