晓的反义词
现在完成时的用法详解
现在完成时：表示过去某一时间发生的动作对现在造成的影响和产生的后果，还有可能一直延续下去。结构为：has/have+过去分词
（黑点表示现在和过去两个时间点，实箭头表示动作在延续，虚箭头表示动作可能继续持续。）
基本用法：
一、 开始于过去的动作一支烟学到现在，对现在有影响。现在完成时跨越两个时间，一是过去，一是现在。
1. Have you wait long ?你等很久了吗(现在还在等着)
2. She has invited my whole family to supper on Sunday.环绕的意思她已邀请我们全家周日去吃晚饭（结果：周日有安排了）
3. She has won prizes for her records and a prize for one of her films.她的唱片曾多次获奖，她的一部电影也曾获奖（结果：奖品在她手里）
二、 现在完成时表示最近发生的动作时，可以与just,recently,already,yet,still,at last终于,finally,almost等副词连用。
1. 小学五年级语文教学总结What good books have you read recently?你最近阅读了什么好书
2. The stone works have already repaired both the tower.我的老师韩国石匠已经修复了两座石塔。
3. Not enough building materials for this project have been collected.为这项工程采集的材料还不够。
4. Has it stopping rraining yet?雨停了吗
5. I still haven’t passed my driving test.我还未通过驾驶考试。
6. At last he has done it.他终于把它做完了。
7. The exact amount has not been finally decided.确切的数目还没有最终确定。
8. The plan hasn’t been finally approved.计划最终还未获得批准。
9. Don’t go without us!We have almost finished the experiment.别被我们留下，我们的实验快做完了。
三、 戏曲特点现在完成时表持续时，虽不能和表示具体的过去时间状语如：justnow,a minute ago,yesterday,last year等连用，但是可以和表示“直到现在”的状语连用，如：before,before now, up till now, up to now, so far, previously, ever, never等连用
1. You have told me all that before.你以前已经把那件事全部告诉我了。
2. I haven’t been here before now.我以前没来过这。
3. Howerver,humans have so far not been wise enough to make correct decisions.然而，迄今为止，人类还不够聪慧到能做出准确无误的决定。
4. I haven’t seen him previously.我以前没见过他。
5. Has she ever talked to you about such matters?她曾经对你说过这些事吗？
6. I have never broken my word.我从不失言。
7. I have heard nothing from him up to now.迄今为止，我还没听到他的消息。
四、 现在完成时表持续时也可以和表示过去一个时间段的时间状语连用，如：in the last… , in the past… , during the last,,, , through centuries几世纪以来，throughout history自古以来，等
1. In the last two years he has sold millions of records.在过去两年他已经售出了几百万张唱片。
2. What has changed in the last /past few months?在过去几个月里这里发生了什么变化？
3. Throughout history man has had to accept the fact that all living things must die,for the very nature of life includes death .自古以来，人类必须接受这样的事实：一切生命体最终都会消失，因为生命的本质包含了死亡。
4. Through centuries the brzarre antics of sleep-walkers have puzzled police.几个世纪以来，梦游者古怪的行为让警察和科学家们大为困惑。
五、 现在完成时表示持续时也可以和表示现在的时间状语连用，如：now, always, often, today, lately, frequently频繁地/经常地，regularly规则地，sometimes,…times, this morning, this week, this month, this year连用，因为现在完成时是一个现在的时态。
1. North Americas have always liked cars.北美人一向喜欢汽车。
2. I have often thought about this.我经常想起这件事。
3. Today I have been very busy.近天我一直很忙。
4. Have you seen either of them already?你最近见过他俩的哪一个吗？
5. I have sometimes had letters from her.我有时候收到她的信。
6. It has rained every day this week.这个星期每天都下雨。
7. How many times have you been there this year?今年你去过那里多少次了？
六、 现在完成时表持续时，经常和since,for连用。Since（介词）+时间点，since（连词）+从句（一般过去时态），for+时间段，since+时间段+ago
1. We have known each other since we were children.我们从小就互相认识了。
2. They have done colour printing in China since the 12tl century.自从12世纪以来，中国就是用彩印刷了。
3. He has visited China for three years.他在中国进行了三天访问。
4. The films has been on for five minutes.电影上演了5分钟了。
七、现在完成时中，表示终止性的动词（即动作开始的时候就已经结束了）的肯定式不能
与表示“一段时间”的状语连用。要用必须改为“be…”延续性动词来表示。现归纳总结一下由非延续性动词到延续性动词的转换：
arrive→be here        begin(start)→be on    become → 利图亚湾海啸be   
come back→be back    come→ be here,      catch a cold →have a cold
die →be dead          eat → have,          leave →be away
go to bed →sleep      fall ill(sick,asleep)→be ill(sick,asleep)       
    get up→be up          go out →be out      get ready→ be ready
    finish →be over    put on →wear/be on      get married→be married
    open →be open    join →be in / be a member of…
    close  →be closed    go to school→be a student
    borrow  →keep      buy →have    make friends→ be friends 
    catch(a cold)→ have(a cold)  get to know →know
    begin to study→study        come to work→work    等
如He has been a soldier for three years.他参军三年了。
    His father has been dead for two years.他父亲去世二年了。
    The film has been on for ten minutes.电影已开始十分钟了。
    We have studied English for three years. 我们（开始）学英语已三年了。
终止性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。
    如：I haven't left here since 1997.自从1997年以来，我一直没有离开过这儿。
八、 1.It is /has been+一段时间+ since从句(一般过去式）
It is /(has been) two years since I became a postgraduate student . 我是研究生已经两年了。
2.”多长时间”+has passed+since从句（一般过去式）
  Three years has passed since he died.他已经死了两年了
  Three months has passed since he came here.他来到这已经三个月了。
九、have been(to)与have gone( to)的区别：have been(to)表示“去过某地（现在已经回来了）”，可用于各人称；have gone(to)表示“去某地了（说话时某人不在当地）”，常用于第三人称，前者可与once ,never,several times等连用，后者则不能。如：They have been to Beijing twice.他们去过北京两次。
    He has gone to Beijing .  他去北京了。