open day

day when the public may visit a place normally closed to them 开放日（接待公众参观之日, 平时该处不对外开放）: an open day at the village school 该乡村学校的开放日.

onyx, oodles, oomph, ooze, op, op (also Op), op art, op-ed, opacity, opague, opal, opalescence, opalescent, opaque, opaquely, opaqueness, OPEC, open, open an account, open cheque, open letter, open out, open prison, open question, open sandwich, open to, open up, open verdict, open vowel, open-air, open-and-shut, open-ended, open-eyed, open-handed, open-handedly, open-handedness, open-heart surgery, open-hearted, open-minded, open-mindedness,