1、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
2、,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. eg.I have know Lisa since my childhood. 我从小就认识丽莎（现在还在继续往来解析：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
3、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. 1.Ive left Shanghai for three days.() Ive been away from Shanghai for three days.( ). 2.I left Shanghai three days ago. ( ) It 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, d
4、ie, join,become等.终止性动词要表示持续时, 可用以下方法: .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. .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 clos
5、ed 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
6、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) 5.现在完成时中的 for 与 since for + 时间段 与延续性
7、动词的现在完成时连用 since + 时间点/从句 I have kept the library book for a week.=I have kept the library book since a week ago. 6. It is /has been +一段时间 + since 从句.自从某事发生已有一段时了. eg. It is /has been two years since my brother joined the army. 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
8、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.常和由 for,since引导的，表示一段时间的短语或从句连用 eg.
9、When I got to know him, he had worked there for twenty years.eg.I saw Li Ping yesterday.We had not seen each other since I left school 现在完成时有两种情况：1，表示过去的动作对现在产生了某种结果；如: I have closed the door. 关门的动作发生在过去，并且现在的门是关着的。2，动作从过去某一时候开始一直持续到现在，并且还有可能再继续下去。如：We have learned English for more than four years. 我学英语的动作是四年多以前就开始的，并且现在还在学。过去完成时指的是动作发生在“过去的过去”。如：The train had left when I arrived at the station. 当我到达车站时，火车已经离开了。我到达的动作发生在过去的某一时候，火车离开的动作比到达的动作还要早，也就是发生在“过去的过去”。注意：也就是说现在完成时是与现在有关的，而过去完成时只是与过去有关。
