The old lady was a kind person, and since she and her husband couldn't finish a whole table of food themselves, she gave the child a piece of sweet potato to eat.
"Yummy, mommy, I want to eat sweet potato too," the child's mouth was the most honest, and they immediately felt that the old lady's sweet potato tasted better than any they had before.
These days, kids' tastes are ruined by snacks. It's rare and much better for a picky, active child to want coarse grains over junk food. It wasn't anything fancy, so the young mother took interest.
