這句話應(yīng)翻譯為：這座城市曾經(jīng)的繁榮家喻戶曉.“繁榮”這個詞是屬于抽象名詞,如money這個單詞一樣,是抽象的,是錢的總稱,而不是具體的RMB或者dollar（美元）,看不見抓不著；同時這也不是前面有所提到的事物,所以不需要加the.而a表示某一或單數(shù)等概念.具體定冠詞與不定冠詞的用法樓主可詳見以下用法.
1.不定冠詞的用法 (1) a用在子音前; an用在母音前.An hour (2) 表同種類的全體,此時a帶有any的意味.A dog is a faithful animal.(=Dogs are faithful animals.) (3) 等于one.I have a sister and two brothers.(4) 等于the same.Birds of a feather flock together.(5) 等于per“每一.”.We work eight hours a day.Ninety miles an hour.(6) a = a certain,表說話者不認(rèn)識此人.Do you know a Mr.Smith?(7) 物質(zhì)名詞或抽象名詞加a (an)即成普通名詞,Asparagus is a grass.(a = a kind of).This is a good cloth for summer.(8) “have (or take) a 抽象名詞”,與抽象名詞的動詞形同義.Let us take am.= Let usm.2.定冠詞的用法(1) 由于上下文的關(guān)系,某名詞所指的東西已非常明顯,或已有一定的范圍,該名詞應(yīng)加the.Shut the door.Please pass me the caster.(2) 表該名詞的總稱.The cow is a useful animal.(= Cows are useful animals.) (3) 前面已提過的名詞,再度提到時前面加the.Once upon a time there was a little boy who lived in a cottage.The cottage was in the country,and the boy lived there all his life.(4) 用于為片語或子句所修飾的名詞之前.This is the book that I promised to lend you.(5) 用在宇宙（獨一無二）的天體名詞之前.The sun; the moon; the sky; the earth.(6) 用在方位,方向等名詞之前.The sun rises in the east and set in the west.(7) 樂器的名稱前要加the.To play the piano (violin,guitar,flute,etc.) (8) 表示單位的名詞前要加the.Gasoline is sold by the gallon.Meat is sold by the catty.(9) 在最高級的形容詞或序數(shù)(the first...)之前要加the.Taiwan is the best place to live in.(10)專有名詞在下列情況可加the.(A) 海、河、運河的名稱：The Thames; the Bahamas;(B) 復(fù)數(shù)形的專有名詞:The West Indies; the Bahamas; (C) 船泊的名稱:The Queen Mary; the Flying Scotsman; the Comet; (D) 書報、雜志、經(jīng)典的名稱：the Times; the Central Daily News; the Koran; (E) 公共建筑、機關(guān)的名稱:The Ritz Hotel; the Ministry of Education; (F) 國民的總稱:the French; the Japanese; the Chinese; (G) 用在姓氏的復(fù)數(shù)前指其全家人:The Chens will move to the country.