have been 这个单词怎么用

have been 这个单词怎么用
We have been working on this project for over a month now和my keys has been lost有什么区别,怎么一个是进行时,一个是过去分词

have been是完成时的一个标志性格式,你所举到的这两个例子前面一句意思是：我们已经在这个工程干了超过一个月了（但现在还没有结束,还要继续干下去）,而第二句意思是：我的钥匙已经丢了（表示现在的结果）.前一句为现在完成进行时,后一句则为一般现在完成时.一、现在完成时 (have/has done,have/has been done) 1.现在完成时常用的时间状语有lately,recently,just,already,yet,up to now,till now,so far,to this day,in the past few years/months/weeks/days,over the past few years,during the last three months,for the last few centuries,through centuries,throughout history等.2.在时间状语从句中,谓语动词可以用现在完成时代替将来完成时.例如：Mother won’t let her watch TV until she has finished her homework.母亲要到她做完作业才让她看电视.The dinner party will begin after all the guests arrive/have arrived.所有的客人到了以后,聚餐就开始了.3.has/have been to与has/have gone to的区别.has/have been to表示“曾去过”,说明有某种经历；has/have gone to表示“已去某地(在途中或已经到达目的地).例如：They have been to Sweden many times.他们去过瑞典许多次了.Jack isn’t in.He has gone to the supermarket.杰克不在,他去超市了.4.现在完成时特别强调瞬间动词和持续性动词.瞬间动词表示短暂、不能持续一段时间的动作,如come,go,leave,start,begin,become,receive,die,而持续性动词表示能持续一段时间的动作,如work,stay,live,learn等.下面列举一些常用的瞬间动词和对应的持续性动词：leave,be away；die,be dead；put on,wear；fall ill,be ill；borrow,keep；catch cold,have a cold；buy,have；join the army,be in the army.例如：My brother has been in the army for some time.我兄弟参军有一段时间了.My brother joined the army some time ago.我兄弟是一段时间以前参的军.He has been up for an hour.他起床有一小时了.He got up an hour ago.他一小时前起的床.Jack has been a soldier for some time.杰克当兵有段时间了.Jack became a soldier some time ago.杰克是在一段时间前当的兵.但是,瞬间动词的肯定结构可以用不与“for+时间段”连用的现在完成时,说明某个动作已经发生；瞬间动词的否定结构可以与“for+时间段”连用,说明某动作不发生的状态可以持续一段时间.例如：Hurry up!The film has begun.快一点!电影已经开始了.We haven’t heard from her for a long time.我们很久没收到她的来信了.5.句型It is/has been + 时间段 + since(从句的谓语动词用一般过去时) 例如：It is two months since they came here.他们来这里两个月了.It is ten years since his father died.他父亲去世有十年了.6.持续性动词用于含有till/until的句子结构,表示该动作一直持续到某时间终止；而瞬间动词的否定结构用于till/until句子中,表示某动作不发生的状态延续到某时间终止,可译为“直到……才……”.例如：They went on working till supper time.他们继续工作到晚餐时间.They didn’t stop wording till supper time.他们一直到晚餐时间才停止工作.I will stay until you come.我会等到你来.I won’t leave until you come.直到你来了,我才会离开.7.句型this is the first/ second/ third … time that(从句的谓语动词用现在完成时) 例如：This is the second time that the products of our company have been shown in the International Exhibition.这是我公司产品第二次参加国际展览会.二、现在完成进行时 (have/has been doing,一般不用该时态的被动语态) 与现在完成时相比,现在完成进行时更强调,在从过去到现在的时间里,动作或状态一直持续或一直反复出现.例如：It seems oil has been leaking from this pipe for some time.We'll have to take the machine apart to put it right.看来,这个管道漏油已有一段时间了,我们将不得不拆卸机器排除故障.At last you come!I have been waiting for you for the whole morning.你终于来了,整个上午我都在等你.希望对你有所帮助~