词根词缀：ag-, agen-, act-, agi-, agit-

【来源及含义】Latin: to set in motion, to hurry, to shake; to drive; to do, to act; to lead, to conduct, to guide

【同源单词】Ab actu ad posse valet illatio, Ab agendo, act, acta, Acta est fabula, acta sanctorum

词根词缀：retro-, retr-

【来源及含义】Latin: back, backward, backwards; behind

【同源单词】arrear, regurgitant menstruation, retroact, retroaction, retroactive, retroactively