Every Sunday morning I take a walk around a park near my home. There's a lake in one corner of the park. Each time I walk by this lake, I see the same old woman sitting at the water's edge with a small metal cage beside her.
This Sunday, I stopped walking and went over to her. As I got closer, I realized that there were three turtles(乌龟)，unhurt, slowly walking around the base of the metal cage. She had a fourth turtle on her knee that she was carefully cleaning it with a brush, which made me feel surprised.
"Hello," I said. "If you don't mind, I'd love to know what you're doing with these turtles."
"I'm cleaning off their shells," she replied.
"Anything on a turtle's shell weakens the turtle's ability to take in heat and blocks its ability to swim. It can also impair and weaken the shell over time."
She went on, "I spend a couple of hours each Sunday morning, relaxing by this lake and helping these little guys out. It's my own strange way of making a difference. "
"Well then, don't you think your time could be better spent? It's a waste of time. And 99% of these turtles don't have kind people like you to help them clean off their shells. So, how exactly are your efforts here truly making a difference?"
The woman smiled, then looked down at the turtle on her knee, wiped off the last piece of algae(海藻) from its shell, and said, "Sweetie, if this little guy could talk, he'd tell you I just made all the difference in the world. "
