专业英语四级

oak oar oath oats obedient object oblige obliging oblivious oblong obscure obscurity observe obstacle obstinate obstruct obtain occasion occur odd offence offend offset offspring oily olive omen omit online onlooker only onward opening operation opium opponent opportunity opposition oppress optics optimal option orchard ordeal order ore organ orient origin originate ornament orphan orthodox ostrich otherwise ounce outbreak outcome outdated outlaw outlet outline outlook output outrageous outset outskirts outstanding oven overall overcast overcome overcrowd overdo overdue overflow overgrown overhear overlap overleaf overlook overnight overrule oversea overseas overtake overthrow overtime overturn overweight overwhelm owing owl oxide oyster ozone