 He will therefore make an indirect request conditional on the elimination of the obstacle and ask, “Do you remember what time the concert is tonight?” which will mean “Do you remember what time the concert is, and can you tell me?” Therefore, if the friend does not remember, he can simply answer “no.”

The second way is illustrated in more frequent and general situations where the obstacle isn't well known or specific.So if the speaker were to ask a passing stranger near the arena about the start time of the concert, he might formulate, “Can you tell me when the concert starts?” The expected obstacle is formed by lack of ability and willingness of the stranger to answer the question.It is a useful convention due to how it provides the stranger with a broad range of graceful excuses not to give the desired answer.