先声xiānshēng指发生在重大事件之前的性质相同的某项事件{first signs; herald; harbinger; another event of the same nature that takes place before an important event}: 1789 年的法国大革命是十九世纪各国资产阶级革命的～。{The French Revolution of 1789 heralded other bourgeois revolutions in the 19th century.}