by accident

偶然

button, button mushroom, button up, button-down, buttoned up, buttonhole, buttonhook, buttress, buxom, buy, buy off, buy out, buy up, buyer, buzz, buzz off, buzz-word, buzzard, buzzer, by, by air, by all means, by all nerves, by analogy, by and by, by and large, by any means, by chance, by choice, by comparison, by courtesy of, by error, by far, by force, by hand, by heart, by instinct, by invitation, by itself, by leaps and bounds,