在學習英語詞匯中，有時同義詞的辨析是很不容易的，我們一般從三方面進行區分，即：語法、語義和文體。語法主要是詞性、搭配、句式等的區分;語義主要是詞義的本義、引申義、比喻義和內涵和外延等的區分;文體主要是正式和非正式、褒義和貶義等的區分。

　　時代

　　period: It indicates any passage of time, great or small.

　　epoch: It indicates a long period of time marked by events or development of a particular kind.

　　The first flight into space marked a new epoch in the history of mankind.

　　era: It refers to a very long period of time marked by a particular feature in a great new era of world revolution

　　age: It shows a particular