[ことがある, kotogaaru](exp, v5r-i) (1) (uk) (after the past tense form of a verb) (something) has occurred; to have done (something); such a thing happened; (2) (uk) (something) happens on occasions; there are times when; (P)[Add to Longdo]
[ことがない, kotoganai](exp, adj-i) (1) (uk) (after the past tense form of a verb) (something) has never occurred; to have never done (something); such a thing has not happened; (2) (uk) never happens; there is never a time when[Add to Longdo]