oratorio

n. 清唱剧

opulent, opus, or, or else, or rather, or so, oracle, oracular, oral, orally, orang-utan, orange, orange squash, orange-blossom, orange-coloured, orangeade, orate, oration, orator, oratorical, oratory, orb, orbit, orbital, orch, orchard, orchestra, orchestra pit, orchestra stalls (US orchestra), orchestral, orchestrate, orchestration, orchid, ordain, ordeal, order, order-book, order-form, order-paper, ordered,