shouldyoudaoicibaDictYouDict[should 词源字典]
should: [OE] Should started life as the past tense of shall. It preserves the word’s original connotations of ‘obligation’ which have all but disappeared from shall.
=> shall[should etymology, should origin, 英语词源]
shouldyoudaoicibaDictYouDict
c. 1200, from Old English sceolde, past tense of sceal (see shall). Preserves the original notion of "obligation" that has all but dropped from shall.