onus

n the onus [sing] (fml 文) duty or responsibility (for doing sth); burden 职责; 责任; 负担: the onus of bringing up five children 抚养五个孩子的责任 * The onus of proof rests/lies with you, ie You must prove what you say. 证明你所言属实的责任在你.

oneself, ongoing, onion, online, onlooker, only, only that, only too, ono, onomatopoeia, onomatopoeic, onrush, onset, onshore, onside, onslaught, onto, onto (also on to), ontological, ontology, onward, onward(s), onyx, oodles, oomph, ooze, op, op (also Op), op art, op-ed, opacity, opague, opal, opalescence, opalescent, opaque, opaquely, opaqueness, OPEC, open,