Teenage boys in a Shanghai school are on the front line of teaching reform after the world's top-scoring education system introduced male-only classes over worries they are lagging girls. Rows of white-shirted boys are put through their paces as they are called up individually to complete a chemical formula by teacher Shen Huimin, who hopes that a switch to male-only classes will help them overcome their reticence. "We give boys a chance to change," she said.