When pronounced as a 4th tone, this character has the meaning "to think/regard as/replace, suitable/adequate, at or in the very same". It's the first meaning I'm interested in. My dictionary gives the example sentence
你当我不知道吗？ Do you think I've no idea?
The problem is, I can't find any more example sentences or articles or information on how to use this or when it's suitable to use it, because 当 pronounced as a 1st tone is more common and all my search results are for that pronunciation.
So my questions are - can anyone provide me some examples of how to use this character (4th tone)? And can anyone explain when to use it? (what is the difference between 你当我不知道吗 and 你以为我不知道?)
Thanks in advance!