现在完成时现在完成时.doc

现在完成时 过去发生的而与现在的情况有关的事或状态， 或者是从过去某时到现在为止这一段时间内发生的情况。 【一定与现在有关系】 现在完成时的用法：“继续”、“完成”、“经验”、“结果”。 My father has worked here for nearly 30 years. 【从过去继续到现在的动作或状态】 I have visited the state of Michigan twice.【过去某时刻发生的动作使现在有某种经验】 I have just finished my homework.【现在已经完成的动作】 I have lost my dictionary.【过去发生了某动作导致现在的结果】 四种用法的时间状语： 继续　since, for, How long~?, all, etc. 经验　often, ever, never, before, once, ~times 完成　already, just, yet, etc. 结果　不需要时间状语 表示继续的现在完成时　【一定要和现在有关系，否则只需要用一般过去时】 I began to study English three years ago. I still study English now. I have studied English since three years ago. 常用的时间状语：for+时间；since+过去某时。 “for+时间”可以和各种时态连用，千万不要产生误解，认为它只用于完成时。 He studied in Beijing University for 4 years in 1960’s.?? 此句是过去时，与现在无关，只是在过去的二十世纪六十年代发生的事，同样可以用“for+时间”。 “since+过去的时间”表示从过去某时开始的动作或状态一直继续到现在，此时，since是介词。 I’ve learned to dance since three years ago. We have known each other since we were children. 注意：通常since引导的从句的动词是用过去时，而主句原则上是用现在完成时，但用“it’s+时间~”开始的句子例外。 It’s ten years since we left school. 其它时间副词：always, often, these days (months, years~), recently (lately), so far=up to now=till now=until now, in the last (past) few years~~~ 表示经验的现在完成时 1. 过去时：Helen read the novel three years ago and she read the novel again and again. 2. 现在时：Now she knows the novel (or Now she remembers the novel). 3. 现在完成时：Helen has read the novel three times. 常用表示经验的时间状语： 置于句中的时间状语（副词）often, ever, never。 注意never的位置，如， No, I never have No, I have never done that. 放在句末的时间状语：表示频率的副词，before, yet She has read the poem once. I have taught English in this school before. have (has) been…辨析 表示完成、结果的现在完成时 【表示结果的完成时，往往不必用时间状语】I finished my homework yesterday. 昨天做完了作业。（和现在无关，现在也许又在做作业） I’ve just finished my homework. 已经做完作业。（现在没有作业可做） I opened the window. 过去的动作 The window is open now. 过去的动作对现在的影响还存在 I have opened the window. 我已经打开了窗户。 表示完成的时间状语（副词）：already, just, yet. 放在句中的副词already, just I have already written a letter to my teacher. I have just phoned him. 注意：already有时也用在疑问句中 Has she arrived at the station a