"I don't know" is a Cantonese proverb, which evolved from a Cantonese sentence. I don't know how to buy a coffin. In Cantonese, "white" has a local meaning, and "not knowing" means not knowing. So this sentence means "I don't know where to buy a coffin", but I have no concept of death.
Extended data:
Common expressions in Cantonese are:
First, catching the word lice-similar to the meaning of "breaking Wen Er" or "picking words" in Mandarin, that is, it is a metaphor for criticizing the negligence of words, or using words flexibly in sound and meaning to attack writers. Or look for loopholes in the document in order to win the lawsuit.
Second, the ghost painting symbol means graffiti, which means mocking others' bad calligraphy.
Third, playing the devil-a metaphor for bad guys fighting with bad guys.
Fourth, the ghost body-metaphor nonsense, incoherent.
5. Hold the hat-that is, close the store.
6. Unpleasant-a metaphor for unexpected things.
Seven, a kick-not kick out, but do all kinds of work.