forerunner: is applicable to anything that serves as a sign, omen, or warning of something to come: the international incident was a ~ to war.   (sign迹象标志: 任何可以感觉到或推理出的迹象implies any indication that can be perceived by the senses or the reason, 如interpreted her smile as a good sign认为她的微笑是个好的迹象，如gratitude is the sign of noble souls感恩是高尚灵魂的标志）  (omen征兆预兆是将要发生的迹象is the sign that something is going to happen，如a good/bad omen吉祥的/不祥的预兆，如an omen of death/disaster死亡/灾难的征兆，如the omens for their future success are not good他们未来成功的预兆不祥)  先驱本义指马车中前面的一匹奔跑的马，引申为在思想上或行为上走在前端的人


precursor: applies to a person or thing that paves the way for the success or accomplishment of another: 18th century poets who were ~s of the Romantics.    （pave the way铺平道路，将石块砖块铺到道路上，使道路平坦泥土不外露，比喻做准备，如the truce paved the way for peace talks这次停战为和谈铺平了道路）  


harbinger, herald: both apply, chiefly figuratively, to one that proclaims or announces the coming or arrival of a notable event or person: robins, the ~s of spring(harbingers); the ~ of a new age in medical science.   （Harbin是哈尔滨英文名，这个词就是哈尔滨人，除了知更鸟robins是春天的预告以外，还有金缕梅，如witch hazels are the harbingers of spring金缕梅预示春天的来临）  herald本意是古代传令官，引申为预告    （proclaim和announce意思相同，都表示宣布declare，但proclaim更强调清楚有力权威implies a clear, forceful, and authoritative declaring，如the president proclaimed a national day of mourning总统宣布全国哀悼）


forerunner先驱或前兆: 指未来事物的先驱或迹象征兆警告，precursor先驱: 为其它人的成功奠定基础的人，harbinger,herald预报者: 主要用在比喻句，表示宣布重要人事到来的人，就像传令官


记忆方法: 1）首字母FPHH想成很佩服<==先驱         （trailblazer也很常用，烧草开路的人，顾名思义表示开路先锋开拓者先驱，新闻报道常用这个词，如海伦托马斯Helen Thomas是美国白宫记者协会首位女主席，在白宫记者席从业50年，提问过众多总统，被称为"toughest journalist"最强韧的记者，2013年她92岁去世时，CBS新闻标题中称她为"trailblazer"，又如trailblazing scientific research创新的科学研究）


         2）先驱的意思是走在前边的人mean one who goes before or announces the coming of another.