2——01·6专升本英语语法.ppt

 If you put your hear into it, you will find it easy. 第一讲. 时 态 英语主要靠动词本身形式的变化来表示动作的时间，副词的作用不大， 语助词几乎没有。 英语的句子，除少数特殊情况外，只要都离不开时态，都以一定的 时态出现。换言之，只要是句子，就有时态问题。理由很简单：一个 句子必须有主语和谓语动词（主要动词），而后者总是用于某一时态。 学英语，时态是逃避不了的，但它并不是一个消极的因素。恰好 相反，它有很强的表达力，能使句子的意思明确，能显示细微的差别， 有时还能使句子生动有趣。 一般英语有12种时态，即现在，过去，将来三大类，每一类中又分为 一般，进行，完成，完成进行4种。 第一讲.时 态 (一)现在完成时 (1)构成 have/has+过去分词 现在完成时的否定式/ 疑问式和简单回答形式: (2)用法 1.在未指明具体时间的情况下,现在完成时动词通常可以表示在说话之前已经完成,而后 果或影响至尽仍存在的动作.现在完成时把过去的动作和现在的结果联系起来.过去时只 限于表示过去的动作本身,与现在的结果无关.例如: 1)He has gone to shanghai. (He went to shanghai and he is not here now.) 他已经去上海了. 2)I have opened the window. (I opened the window and the window is open now.) 我已把窗户打开. 3)I have bought an umbrella. (I bought an umbrella and I have it now.) 我买了一把伞. 4)The concert has started. (The concert started and is now going on.) 音乐会已经开始. 5)I have had breakfast. (I had breakfast and I am not hungry now.)我已吃过早饭. 注: have gone to和have been to在意义上有区别.例如: 1)He has gone to Hangzhou.他到杭州去了. (他已前往杭州,或在途中,或已到达.说话人认为他现在在该地.) 2)He has been to Hangzhou.他曾到过杭州. (说话人认为他过去到过杭州,现在已经不在该地.)  2.现在完成时动词可以表示开始于过去持续到现在(也许还会继续进行下去)的动作或状 态.例如: 1)I have studied English since 1975. 我从一九七五年起就学习英语. 2)They have been in Beijing since 1949. 他们从一九四九年起就(住)在北京. 3)He has lived here for two years. 他住在这儿已经两年了. 4)He has been ill for ten days.他病了十天了. 注:come, go, leave, arrive, join, die, bury, 和marry等动词所表示的动作是一时的, 不能延续的,故不能与for …, since …等开头的表示一段时间的状语连用. 如不能说:*He has come to Beijing for seven years. *He has left Beijing for two years. *He has joined the Army for three years. *His father has died for five months. 可以说:He has been in Beijing for seven years. He has been awa