Guo says he learned a lot from his grandfather. He listened to Tao's volunteer experience when he was a toddler, and began doing community work under the guidance of his grandpa.

But Guo is not just learning. He's now also teaching his grandfather English.

Tao doesn't speak English, but he is clear that "as an Olympics volunteer, I have to learn it to at least be able to communicate a bit with foreign guests".

"It's never too late to learn," Tao says. "I don't expect to become an English-language master, but I hope that I can at least say 'Welcome to Beijing' when I meet with foreign athletes and guests."