過去は過去

かこはかこ

the past is the past; let bygones be bygones

過去

かこ

a past (i.e. a personal history one would prefer remained secret), one's past

過ぎ去る

すぎさる

to pass, to pass away

過去形

かこけい

past tense

過去帳

かこちょう

(family) death register

大過去

だいかこ

pluperfect

過去世

かこぜ

one's previous life

過去問

かこもん

past (exam) question collection

過去作

かこさく

past work (book, film, etc.); previous title

近過去

きんかこ

recent past tense (e.g. passato prossimo in Italian); present perfect

遠過去

えんかこ

remote past tense (e.g. passato remoto in Italian)

過去生

かこせい

one's previous life

半過去

はんかこ

imperfect tense

過去ログ

かこログ

archive (of an online mailing list, message board posts, etc.)

過去１

かこいち

most... ever; most... up to now; more... than ever before

過去の再審

かこのさいしん

historical revisionism

過去の遺産

かこのいさん

legacy of the past

相場に過去はない

そーばにかこはない

(market maxim) there is no past in the market (advice not to regret the past but to focus on the future)

物になる

ものになる

to prove successful; to take hold; to amount to something