open-air

a.户外的

opal, opalescence, opalescent, opaque, opaquely, opaqueness, OPEC, open, open an account, open cheque, open day, open letter, open out, open prison, open question, open sandwich, open to, open up, open verdict, open vowel, open-and-shut, open-ended, open-eyed, open-handed, open-handedly, open-handedness, open-heart surgery, open-hearted, open-minded, open-mindedness, open-mouthed, open-plan, open-work, opencast, opener, opening, opening night, opening-time, openly, openness,