Margie and Tommy had mechanical teachers. They were large and black and ugly and flashed on large black screens on which all the lessons were shown and questions were asked. These mechanical teachers had a slot in which the students had to put their homework .
Turn-yielding cues relinquish control of the conversation. We might look at the listener more steadily or remain silent for a noticeable period to indicate that we are finished making a point. Turn-maintaining and turn-yielding may also be expressed explicitly. It's a conversational turn.
