Episode #3.8 - S3-E8
Continuity mistake: During the mime class when Mr. Sutcliffe says "let's get down to some mime" Tracy is about to sit down. The angle changes and Tracy has sat down without having had enough time to move. Also there is no-one sitting on the floor between Duane and Tracy, but when the angle changes Duane and Tracy are sitting further apart, and the girl in the red and white top who was sitting behind them is now between them. Another angle change and all the other kids have changed position.
