suggests现在完成时态
（1）表示发生在过去的动作或存在的状态到说话时刚刚完成或结束，通常使用不具有延续意义的动词，arrive, become, begin, break等。这种用法可带有迄今意义的时间状语，如up to now, so far, already, 等。也可带有包括现在时间在内的时间状语，如now, recently, in the past few years, just等。
I have already posted the photoes.我已经把照片寄出了。
I have just finished my work.我刚刚完成工作。
(2)表示从过去某时开始一直延续到现在的动作或状态，也许还将继续下去。这种用法通常用于具有延续意义的动词，如live, stay, work等，并带有表示时间段的状语或迄今意义的时间的状语，如for, since等。
You don't need to describe her. I have met her several times.你没必要描述她，我见过他好几次了。
--I'm sorry to keep you waiting. —对不起，让你久等了。
--Oh, not at all. I have been here only a few minutes. — 噢，没关系。我刚来几分钟。
They have lived here since 1989.他们自从1989年以来就住在这里。
I haven't seen her these days.这些日子我没见到他。
注意：表示短暂的动作动词或状态动词不能用于这种用法，如arrive, come, go, leave等。如，不能说：She has come to our school for 2 years.
(3)表示到现在为止的一段时间内重复发生的动作。常与often, always 等连用。
He has been late for class every morning this week.这个星期他每天早晨都迟到。章程修正案
Eight times he has tried and eight times he has failed.他试了八次，八次都失败了。
My father has always gone to work by bike.我爸爸一向骑车上班。
（4）用于时间、条件状语从句中，表示将来要完成的动作。
He will be back before I have finished my work.我完成工作之前他会回来的。
We will set off if it has stopped raining.如果雨停了我们就出发。
（5）用在从句中，表示一个动作先于另一个动作
I understand what she has said to me.我理解她对我说的话。
We know that he has passed the English exam.我们知道他英语考试及格了。
（6）用在“It(This) is(will be ) the first/second/third…time+ that从句”中
在这种从句中，当主句动词为is/will be时，that-从句的动词用现在完成时，that 可以省略。主句中的主语还可用this, this evening等; 这种结构中的first也可用其他序数词；time也可由其他名词替代。
-Do you know our town at all?你对我们城镇熟悉吗？
-No, this is the first time I have been here.不熟，这是我第一次来这里。
It's the first time I've been here.这是我第一次到这里来。
It'll be the first time I've spoken in public.这将是我第一次当众讲话。
（7）“It (This)is the best( worst, most interesting等) + 名词+从句”结构中的从句要求用现在完成时
This is the best film I’ve ever seen.这是我所看过得最好的一部电影。
This is the most interesting novel he has ever written.这是他写得最好的一部小说。
（8）现在完成时可以表示反问的语气（与when连用）或感情彩
- Who is Jerry Cooper? 杰利·库珀是谁呀？
- Haven't you met him yet? I saw you shaking hands with him at the meeting. 你还没见过他？我看见你和他在开会时握手了。
Now you’ve done it.你这下可闯祸了。
When have I been treated like this?我什么时候吃这一套？烤羊腿的做法烤箱
过去完成时态
（1）过去完成时表示在过去某一时间或动作以前已经完成了的动作。这个过去的时间状语有营养粥的配方by, before等介词短语或when, before等引导的从句。
Helen had left her keys in the office so she had to wait until her husband came home. 海伦把钥匙忘到办公室里了，因此她不得不等她丈夫回来。
背起爸爸上学
When we got to the cinema, the film had already begun.当我们到达电影院时，电影已经开始了。
He told me that he had visited the Great Wall before.他告诉我他以前参观过长城。
By the end of the match, they had kicked 2 goals, and we had kicked 4.比赛结束时，他们踢进了2个球而我们踢进了4个球。
（2）表示动作在过去某一时间之前开始，一直延续到过去的这一时间，而且还可能继续下去的动作，常和for, since构成的短语或引导的从句连用。
By the time I left the school, he had taught the class for 3 years.到我毕业时，他已经教那个班三年了。
He said he had made great progress since he came here.他说自从他来这里他已经取得了很大进步。
（3）用于表示与过去事实相反的虚拟条件从句或如何缓解学习压力as if从句中表示与过去事实相反
I should have called you if I had known your telephone number.假如我过去知道你的电话号码，我就给你打电话了。
He described the scene as if he had been there.他描绘的景如同他去过那里一样。
（4）表示假设的宾语从句
放在像said，told，asked，thought，wondered等过去时动词的后面，表示在这些动作发生之前已经发生了的事情。
My friend told me that he had passed the exam.我的朋友告诉我，他已通过了考试。
He asked me whether I had seen the film the night before.他问我头一天晚上是否看过那部电影。
She wondered who had left the door open.她想知道谁敞着门的。
（5）用在 "It was the first/second/third…time that…”句型中
在此句型中，主句用了一般过去时，that引导的定语从句要用过去完成时。
This was the first time they had met in thirty-nine years. 这是39年里他们第一次见面。
It was the first time we had spoken together. 这是我们第一次在一起说话。
（6）intend, mean, hope, want, plan, suppose, expect, think等动词的过去完成时可以表示一个本来打算做而没有做的事
这种结构也可以表示过去未曾实现的设想、意图或希望等，含有某种惋惜。
I had intended to call on you yesterday, but I had an unexpected visitor.我本来昨天打算要去看你，但我来了个不速之客。
We had meant to tell her the news but found that she wasn’t in.我们本想把这个消息告诉她的，但发现她不在家。
（7）过去完成时常用结构有“hardly, scarcely, barely … when, no sooner… than等副词的句子里。
She hardly had gone to bed when the bell rang.他刚睡下铃就响了。
No sooner had they left the building than a bomb exploded.他们刚刚离开大楼，一颗就爆炸了。
（8）当before , after, as soon as 等引导的从句里的动作与主句的动作紧接时，由于这些连词本身已经说明了两个动作发生的先后关系，因此两个动作均可用一般过去时表示。
We had breakfast after we did morning exercises.做完早操之后，我们吃早饭。
The train started to move just before we reached the station.我们到车站时火车刚开动。
As soon as they got there, they started to study.他们一到那里就开始学习了。