现在完成时构成: have/has+done1. 表示动作发生在过去，并且一直持续到现在。例如：He has worked in a car factory since graduation.We have been good friends since middle school.How many letters have you received this week?He has made several trips to Paris this year.2. 表示过去一件事对现在造成的结果或影响。例如：Ive lost my key.我的钥匙丢了。（因此无法进屋）She has gone to town. 她进城了。（现在在城里）Ive washed my car. 我洗过车了。（因此车干净）现在完成时常用的时间状语有：already, since, so far, up to now, recently, lately, in the pastdays/months/years等。 1. When you are hom
