accidental

a.意外的，偶然(发生)的

accentuate, accentuation, accept, acceptability, acceptable, acceptably, acceptance, accepted, accepting, acceptor, access, access road, access time, access to, accessibility, accessible, accession, accessory, accident, accident-prone, accidentally, acclaim, acclamation, acclimate, acclimatization, -isation, acclimatize, acclimatise, acclivity, accolade, accommodate, accommodating, accommodation, accommodation address, accommodation ladder, accomodate, accompaniment, accompanist, accompany, accomplice, accomplish, accomplished,