6单元语法

1.现在完成时态(初步了解)
▲现在完成时态的构成
助动词have／has＋动词的过去分词
动词的过去分词一般由动词原形加－ed构成,还有很多不规则变化.基本上和动词的过去式一致.
关于现在完成时态的否定句、疑问句等句式变化,都由have／has来调节完成.
▲现在完成时的基本用法
①表示过去发生的某一动作对现在造成的影响.
I have just received a letter from my brother.
我刚刚收到我哥哥的来信.
Have you seen the film?
你看过这部电影吗?
I have been to New York three times so far.
我到现在为止已经去过纽约3次了.
②表示过去已经开始,持续到现在的动作或状态,往往和表示一段时间的状语连用.
I have not seen him since last January.
我自去年一月就没有看见过他.
Li Hong has been abroad for three years.李红已经出国3年了.
Up till now he has won five prizes.
到现在为止他已赢得5块奖牌了.
③现在完成时常与不确定的时间状语连用.如：already,never,ever,just,yet,before,up to now,so far,for the last few weeks等,表示“到目前为止”所发生的动作.
She has just got a little cold.她只是有点感冒.
Have you read this book?你看过这本书吗?
Has he paid the doctor yet?他给医生交过钱了吗?
I have never met such a strange person.
我以前从没遇见过这么奇怪的人.
It hasn’t rained for six months.已经6个月没有下雨了.
Great changes have taken place in this city in the last five years.
在最近的5年当中,这个城市发生了巨大的变化.
④现在完成时还可以和包括现在在内（到说话时仍未结束的）的,表示一段时间的状语连用,如；now,today,this morning／afternoon／evening／week／month／year／these days,since,for a long time等.
I have finished my homework now.
我已经完成了我的家庭作业.
They have visited the Great Wall today.
他们今天游览了长城.
We have had enough rain this autumn.
今年秋天我们这里的雨水很足.
2.现在完成进行时态
现在完成进行时态,表示从过去某一时刻开始一直延续到现在的动作,这动作可能仍然在进行.如：
What books have you been reading these days?
这些天你都看些什么书?
I’ve been sitting here all afternoon.
我在这儿坐了一下午了.
They have been collecting stamps for ten years.
他们收集邮票已经10年了.
Has she been watching TV?她一直在看电视吗?
这是新目标英语 不知道你是什么