前缀pro-来自拉丁介副词pro，基本义为forward，forth (向前）或out (出）。作为原生词缀pro-只与拉丁词根相结合， 其读音为/pre-/或/pro-/。pro-后来也被英语同化为派生词缀，能与名词相结合，表示 in favour of (亲，赞成）或in place of (代， 副）的意思，对名词起修饰作用，这时pro-读音为/praii-/。

先来分析原生词缀pro-与词根结合的几个词例。

proceed [ pro- = forward 向前;ceed = to go or move 运动→] v. move forward; go on after a stop 进行；继续进行 / Please proceed with your story.请把故事接着说下去。

proceeding n. 进程；进行；程序

proclaim [pro- = forth or out 出；claim = to shout 喊=>“to shout out 大声说出 ”→] v. make known publicly or officially 宣告；公布 / A new law was proclaimed yesterday. 昨天颁布了一项新法令。

proclamation n. 宣布，公布；声明 

proclamatory a. 公告的；宣言的

produce [ pro- = forth 前；due = to lead or bring 引带；-e=>“to bring forth 引起，使产生”→] v. bring into existence by labour; create 生产；制造 / The factory produces cars. 该厂生产小汽车。

product n. 产品；产量；成果 

production n .生产；制作 

productive a. 生产的；生产性的