Think of the senior students of England's Royal Ballet Schoolseen here in an exchange with the American Ballet Theatre Studio Companyas the equivalent of interns emerging from a topflight medical school. They're gifted, rigorously trained young people on the threshold of demanding careers, but still unseasoned. In a program divided between 19th- and 20th-century classics (Petipa, Ashton) and serviceable contemporary pieces (Kirk Peterson, Robert Hill, Paul Boyd), they were thwarted by exactitude. Their schooling has planted an indelible image in their minds of how each step should be done and how it should look. And their obedient-student adherence to that vision, especially in the golden oldies, stymies the flow that lies at the heart of dancing. With exceptions. My bets for a glorious future are on Joseph Caley, a fresh-faced and courageous high flier who might be the hero of a child's adventure storyprodigious in his skills, ingenuous in his beauty.