是副詞，這里不是比較級，本身就這樣的，不過帶有比較意味當然，late 的比較級是 later較晚地; 后來We later learnt that this wasn't true at all.我們后來了解到根本不是這么回事 。I'll call again later.我以后再打電話來 。He fell ill on Monday and died three days later.他星期一得病, 三天后就死了 。Tom and Mary got married in 1985.Two years later, they were divorced.湯姆和瑪麗1985年結婚, 兩年后他們離婚了 。
【seven years later中的later什么詞性，他不是比較級么】