There are about seventy thousand Americans living in mainland China today, according to the Chinese and US governments. A lot of the Americans in China only stay for a few years, but then there are others — American ex-pats who’ve lived in China for a decade or more with no foreseeable plans to come home. Who are they? And how Chinese do they become? Evan Osnos has this story, which starts with an ex-pat named Kaiser Kuo. Evan is a staff writer at The New Yorker and author of the book Age of Ambition: Chasing Fortune, Truth, and Faith in the New China. (29 minutes)