all the tasks(having been finished)ahead of time是一个状语从句,不是单独的句子,用来修饰后面的they decided to go on holiday for a week 。在英语里面,一个句子只能有一个主语一个谓语。所以have 是非谓语动词,要变形。而all the tasks对于have来说是施事,所以have加ing...
呵呵,这是一句话,前边的all the tasks(having been finished)ahead of time为表示原因的,它就等于:Because all the tasks had been finished ahead of thime, they decided to go on holiday for a week.或者All the...