M2U1 Grammar and usagePresent perfect tense & Present perfect continuous tense一、 现在完成时1、 构成 have/has done2、用法I 表示过去发生的事对现在具有影响
1) Justin has disappeared, so Kelly is very sad
2) The boy is happy
He has caught a bird
II 表示过去开始的动作一直延续到现在或者还将持续下去
1)I have not seen Justin since Last Friday night
2) Daniel has lived in Beijing since he came to China
III 表示动作的确切时间不明确或不重要
此时下列词汇经常和现在完成时连用: already, ever, never, for, just, lately/ recently, since, yet
1) The boy has already come home
2) I haven’t heard anything from him yet
其中,for + 一段时间,since + 某个时间点
We haven’t seen him for two days
We haven’t seen him since last Monday
IV 表示到现在为止的一段时间内重复的动作
1) Some villagers say that they have seen UFOs many times
2) I have advised him to give up smoking many times, but he just won’t listen to me
V 现在完成时