Ballet master Francis Sinceretti, a former principal dancer with the national Ballet of Holland and other European companies, will teach the finer points of classical ballet's pas de deux, the duet, at this year's classical ballet Mia Arbatova Excellence Masterclasses from April 20-24. The students, 10 girls and 10 boys, have been chosen from ballet schools around the country. At the end of the workshop, the best student will get a summer school scholarship to a top ballet school abroad. This year it is the one affiliated with the Canadian National Ballet in Toronto. The masterclasses are sponsored by the Mia Arbatova Trust and Matan.