Unit 9 Have you ever been to a museum?课文重难点讲解现在完成时一．概念：现在完成时（Present Perfect Tense）过去发生并且已经完成得动作对现在造成影响或后果，也可以表示过去某一时间开始并一直持续到现在得动作或状态。 二、 时间状语：1、 just, already, yet, ever, recently, before, twice, three times, so far, up to now, till now2、 since+（过去时间)时间点, since +一段时间+ ago, 与 since +从句（从句用一般过去时）since yesterday, since last week, since last Monday, since last month, since last spring, since last term, since last year, since 1949, since 1978;since half an hour ago, since two days ago, since three weeks ago, since four months ago, since five years ago;since I became a teacher, since he went to college, since she joined the army；3、 for+一时间段for an hour, for two days, for three weeks ,for four months, for five years4、 in the last few hours, in the last few days, in the last few weeks, in the last few months, in the last few years5、 in the past few hours, in the past few days, in the past few weeks, in the past few months, in the past few years 三、 谓语构成：have/has + 过去分词四．用法说明：1、表示过去某个时间发生得动作对现在得影响或结果，常与 just, already, yet, recently, before, twice, three times 等时间状语连用，如：I have seen the film already、 我已经瞧过那部电影了。(现在我知道电影得内容了。)Have you seen my bag? 您瞧到我得手提包了吗? (您知道它在哪里? )2、 表示过去发生得动作一直延续到现在，并且有可能继续延续下去，常与“since+时间点”，“for+一时间段”，及 how long, (ever) since, ever, before, so far, in the last/ past few years, up to now, till now 等时间状语连用。如：She has been a dancer for ten years、 她已当了十年得舞蹈演员了。We’ve planted thousands of trees in the past few years、 过去几年我们种了成千上万棵树。So far ther...
