语法 -- 现在完成时

构成: have/has + 过去分词

用法: 主要用来表示完成某事或某一动作持续到现在的状态

• 一. 表示说话时已经做完某事

此时常与 already, yet, just, by this time, so far 连用
* Her latest novel has already run to three impressions.

• 二. 表示过去的某一动作或行为一直持续到现在

此时常用的时间状语: all my life, all the time, all day, since, since then, since last year, since two days/weeks/months/years ago, for a long time, up to now, so far, in the past, last few years...
* I've lived here all my life.

• 三. 在时间，条件等状语从句中，代替将来完成时

*