We'd been cornered outside a 7/11 and were getting a lecture on professional ethics. "It's a simple exchange," the professor said. "You contribute a little bit to the cause and we're endlessly grateful in return." Our thoughts on this gentleman's forwardness notwithstanding, the prospect of such a boundless return on investment did stimulate a little charity on our part.Learning Cantonese? You've probably noticed by now that most native Cantonese speakers have around a million ways of saying thanks. We strongly suspect that some are even paid professionally to dream up more each day in order to confuse tourists, mainlanders and everyone else passing through the city. But fortunately, there are only a few dozen variants in common usage, and in this podcast we'll set you right so you know how and when to use them.