did (v.)youdaoicibaDictYouDict[did 词源字典]
Old English dyde, past tense of do (v.). The only remainder in Germanic of the old linguistic pattern of forming a past tense by reduplication of the stem of the present tense. Far back in Germanic the equivalent of did was used as a suffix to make the past tenses of other verbs, hence the English -ed suffix (Old English -de). [did etymology, did origin, 英语词源]