一、时态讲解：现在完成时 （ 1 ）构成：现在完成时由助动词 have + 过去分词构成，助动词 have 有人称和数的变化。第三人称单数用 has ，其余用 have. 现在完成时的否定式直接在助动词后面加上 not 、疑问式是把助动词提到主语之前。以 study 为例，其否定式、疑问式和简单回答形式如下： 否定式 疑问式 I have not (haven’t) studied…. Have I studied…? You have not (haven’t) studied…. Have you studied… ? He has not (hasn’t) studied…. Has he studied…? 否定疑问式 简单回答（肯定 / 否定Have I not (Haven’t I) studied…? Yes, you have. No, you haveHave you not (Haven’t you) studied…? Yes, I have. No, I haven’Has he not (Hasn’t he) studied…? Yes, he has. No, he hasn’（ 2 ）用法： 1 ） 现在完成时 通常表示在 说话之前已经完成的动作 或存在的状态。说话人强调的是该动作或状态对现在的 结果或影响 。 My daughter has just gone out. 我女儿刚出去。 I’m sure we’ve met before. 我肯定我们以前见过面。 She has arrived. 她到了。 2 ）表示持续到现在的动作或状态，往往和包括现在在内的表示一段时间的状语连用，如 recently, already, just, lately, fo r…, since…, yet 等。如： I haven’t heard from her these days. 这些日子我没有收到她的信。 We haven’t seen you recently. 最近我们没有见到你。 They have been away for two years. 他们离开已经两年了。 She has been with us since Monday. ★ 注意： a) since 和 for 的区别 since 后接时间点，如 1993 ， last term, yes terday, the time I got there for 后接一段时间，表示 “ 长达多久 ” ，如 ten years, a while, two days 等。 Ex ercise : 用 since 和 for 填空 1. Jim has been in Ireland ______ Monday. 2. Jill has been in Ireland ______ three days. 3. His aunt has lived in Australia ______15 days. 4. Mary is in her office. She has been there ______ 7 o'clock. 5. India has been an independent country ______1974. 6. The bus is late. They...
