why didn't we know?

I was doing a search for a good korean-english online dictionary recently, and google was kind enough to point me to a forum in yahoo!. turned out to be for koreans trying to learn english. under the heading "phrases of the day" were several innocent phrases like "the weather today is beautiful" and "I need to make a doctor appointment." then it said, "we didn't know he was schizophrenic." y'know, when I'm learning a foreign language, that's one phrase I always try to get down asap. it comes in handy so often. well, at least as a blog title.