
Well in Chinese, the meaning of this short sentence is more or less show you a special conversation, in which U wanna ask a question about sth for a better understanding while the person U asked to felt a little impatient, might sometimes the impatience is friendly, sinse he or she think the answer is so abvious and easy to be found out by youself and your question seems a little ironic, so, this sentence will naturally be used to express the impatience or means the conclusion or sth else U ve mentioned is so obvious.
Hope my explanation would be helpful to U guys@@


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