词根词缀：pro-, por-, pur-

【来源及含义】Greek > Latin: a prefix signifying before; forward, forth; for, in favor of; in front of; in place of, on behalf of; according to; as, to place before; to go before or forward, to throw forward

【相关词根词缀】 Related before-word units: ante-; antero-; anti-; pre-.

【同源单词】portend, portent, portentous, portentously, portentousness, pro

词根词缀：re-, red-

【来源及含义】Latin: back, backward, again; used as a prefix

【同源单词】recalcitrant, recant, recapitulate, recapitulation, recede, receipt

词根词缀：reciproc-

【来源及含义】Latin: reciprocus, turning back the same way, alternating; turning backward and forward; to give, to do, to feel, or to show in return

【相关词根词缀】 Inter-related cross references, directly or indirectly, involving word units meaning "another, other, different, alternating, varied, changing": ali-; allo-; alter-; allelo-; hetero-; mut-; poikilo-; vari-.

【同源单词】reciprocal, reciprocal altruism, reciprocal cross, reciprocal determination, reciprocal hybrids, reciprocal inhibition