现在完成时a.ppt

* **现在完成时** 现在完成时是由助动词have（has）+过去分词构成 其否定句在Have/has后加not. 一般疑问句把have/has提到主语前. 动词的过去分词：规则变化（和过去时一样） 不规则变化： 不规则变化： am/is-was-been are-were-been begin-began-begun break-broke-broken do-did-done draw-drew-drawn drink-drank-drunk drive-drove-driven eat-ate-eaten fall-fell-fallen fly-flew-flown forget-forgot-forgotten give-gave-given go-went-gone grow-grew-grown hide-hid-hidden know-knew-known lie-lay-lain ride-rode-ridden ring-rang-rung show-showed-shown see-saw-seen sing-sang-sung speak-spoke-spoken take-took-taken come-came-come run- ran – run become-became-become 1。表过去发生的某一动作对现在造成的影响或结果,例如 I have just cleaned my clothes. 我刚洗过衣服。 （“洗衣服”是发生在过去的动作，对现在造成的结果是“衣服干净了”） I have just had my breakfast. (对现在的影响：不饿) 通常与表示包括现在在内的时间副词 just（刚刚）, already（已经）, before, yet（一般疑问：已经；否定句：还） never, ever等状语连用 ① I have never heard of that before. ② Have you ever ridden a horse? ③ She has already finished the work. ④ Have you milked the cow yet? Yes, I have done that already. ⑤ I’ve just finished my homework. ⑥ He has not come yet. 2。表示过去已经开始，持续到现在的动作或状态，也可以表示实质可能继续下去的动作或状态。通常和 for（段时间）, since（点时间） 引导的时间状语连用.以及 so far, by now, these days, in the last ten years 等连用。 I have been here for just over two years. He has worked here since 1989. 从1989年， I haven’t seen her these days. She has learnt English for 3 years/since 3 years ago. They have lived here since 1990. What has happened to the USA in the last 350 years? 注意点一： 现在完成时与一般过去时的用法比较 现在完成时表示过去的动作一直延续到现在甚至会继续下去或表示过去的动作对现在造成的影响；一般过去时表示动作发生的时间在过去。现在完成时属于现在时态范围，因此，不能和表示过去的时间状语连用。 如：yesterday, last night, two weeks ago等 试比较： The plane has arrived . 飞机已经来了。（说明现在的情况：飞机在这儿） The plane arrived a quarter ago. 飞机是一刻中以前来的。（强调动作发生的时间在过去） I have taught here for fifteen years. 我在这儿已经教了十五年。（表示十五