WINSTON — The pitched trills of opera filled the gym Tuesday afternoon at McGovern Elementary School. Portland Opera To Go, a small troupe of opera singers traveling around Oregon and Southwest Washington performing for children, made stops at McGovern Elementary and Winston Middle School. The performers put on a 50-minute English adaptation of Wolfgang Mozart’s “The Magic Flute.” Before the show started at McGovern Elementary School, the troupe’s tour manager, Sammuel Hawkins, explained what makes opera unique. “In opera, almost every single moment of the show is accentuated with music,” he said. “These singers have special training. They have a …