Isabelle Carson-Dewitt practices her solo during a rehearsal at the Summer Youth Conservatory Monday at the Center for Dramatic Art. The conservatory, in its fourth year, provides youth ages 10 to 18 with five weeks of theater training from professionals. The program will culminate with a performance of the musical “Drood: The Mystery of Edwin Drood,” based on the final novel by Charles Dickens, at the end of July.