分类：教育/科学-学习帮助
问题：whatisdifferentbewteenHadBeenand? 
how to use them 
回答：㈠.现在完成时表示到目前为止已经完成，并对现在留下某种后果和影响的动作。                结构：助动词have/has + 动词的过去分词                   用法: 1.表示过去发生的某一动作对现在造成的影响或结果,常与一些时间状语,如:already, yet, ever, never, just, before, once,twice等连用,也可以和包括现在在内的时间状语,如these days,today,this year,so far等连用.   eg.I have already posted the letter. (信已经不在我这儿了)                     2.表示过去发生的动作或存在的状态,一直持续到现在,也许还将继续下去,可以和表示从过去某一时刻延续到现在的一段时间的状语连用,即for +时间段,since+时间点/从句, in the last ten years等,谓语只可用延续性动词.                    解析：  1.英语动词根据词义可分为两种,一种是延续性的,一种是终止性的,终止性动词(也可称为非延续性动词,瞬间动词,或点动词),如begin,start,die,buy,leave, come等,表示动作的发生与结束于一瞬间完成,不能再延续,所以它的现在完成时不能和表示延续的时间状语连用,即不能与表示一段时间的状语,for+时间段, since+时间点/从句连用,也不能用在how long引导的特殊疑问句中.  eg. I've left Shanghai for three days.(×)I've been away from Shanghai for three days.( √ ).I left Shanghai three days ago. ( √ )It is /has been three days since I left Shanghai.( √ )                        2.初中英语课本中常见终止性动词有:leave, go, come, arrive, begin, buy, borrow, die, join, become等.终止性动词要表示持续时, 可用以下方法:                   ⑴.将时间状语改为时间段 + ago,句中谓语动词用一般过去时.   eg.我弟弟参军两年了. My brother joined the army two years ago.                   ⑵.若保留for+时间段,since+时间点/从句, 或用在 how long 句型中,则需将终止性动词改为相应的状态动词或延续性动词                           常见终止性动词与延续性动词(或状态动词)的对应关系如下:come/go/arrive/get/reach/move------be in/at open-----be open die------be dead close----be closed become---be borrow---keep begin/start-----be on put on----wear leave-----be away (from) buy-----have fall asleep----be asleepend/finish-----be over catch a cold-----have a cold join the army----be in the army be a soldier join the Party----be in the Party be a Party member →My brother has been in the army for two years.→My brother has been a soldier for two years.                   3.现在完成时中been to,gone to和been in/at been to去过某地,表示某人的一种经历,可以和once,twice,already,ever,never等连用.   eg. She has been to Shanghai twice. (表示目前人在这里)                     gone to 去某地了,说话时某人已离开此地,在去某地的途中或已在某地,   eg. She has gone to Shanghai。 (表示现在她人不在这里)                   been in/at 逗留在某地(已经一段时间).常和for ten days,since I came here等连用.   eg. She has been in Shanghai since she moved there. ㈡.过去完成时??表示过去某一时间或动作之前已完成的动作            结构： 助动词had + 动词的过去分词               用法： 1.表示在过去某一时间或动作之前已经发生或完成了的动作,动作发生的时间为“过去的过去“.表示过去某一时间可用by,before 等构成的短语,也可用when,before等引导的从句或通过上下文表示.   eg. By the end of last term,we had learned a thousand English words.    He had finished his homework before his father came back last night.                    2.表示过去某个时间之前发生的动作或状态, 一直延续到这一过去时刻,或还将继续下去.    eg. When I got to know him, he had worked there for twenty years.(注意) 否定式 had not == hadn't 推荐看:   "初中英语百题精讲"