Why can't you drink cold water right after sport?
Although I disagree with the premise of this paragraph, since I didn't grow up with the Chinese belief that cold drinks are bad for you, in some ways I'm heartened to see that English is being used to transmit Chinese cultural norms. Too often, English textbooks use "Western" examples and scenarios, which I think must be somewhat alienating. By now, learning English is not like learning a foreign language "just for fun" that you'll never use, and so the idea that it must be tied to learning American or British culture is beginning to become a bit less relevant. I'm always trying to tell my students that a language can be used by anyone, and that their goal is not to become like "Western" English speakers, but to develop their own use of English as individuals with a Chinese cultural identity. (Not in so many words, of course.)