This is an example of conversational repair between the teacher and Tim which is similar to that involving Phillip in Chapter 2.The misunderstanding which is indicated by Tim's answer to the first rather than the second of the teacher's questions is cleared up and the dialogue continues with time for justification on both sides. In contrast, Black points out, when Sian is called upon she presents a minimally correct answer, which is accepted by the teacher without a request for justification. In the context of the whole discussion and repeated similar incidents, Black suggests that Sian is regularly used as a pace- maker in the class, a who can be relied upon to provide a correct answer and so allow the lesson to move on, repairing time "lost" in discussions that involving Tim: she is positioned as a "domestique":