1.这本小说有助于帮你了解中国的过去和现在
This novel helps you know about China's history and future.
2.深圳已经变成一个现代化城市
shenzhen has been be a modern city.
3.然而,要见到我老朋友变得更困难了
However,it will be more difficult to meet some of my old friends.
4.飞机已经起飞了
The plane has been flown away.
这是一些现在完成时的资料,你看看吧,希望对你有帮助.
讲解如下：
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现在完成时用来表示之前已发生或完成的动作或状 态，其结果的确和现在有联系。动作或状态发生在过去 但它的影响现在还存在；也可表示持续到现在的动作或 状态。其构成： have (has) +过去分词。
现在完成时的基本构成方式是用动词have加上过去分词。它是用来表达过去发生事情的另一种方式。
He has studied English and French.
他学习过英语和法语。
I have read many books.
我读过很多书。
通常一个动词的过去分词和他的过去式是一样的，但是有一些动词的过去分词有不规则的形式。
be been
go gone
come
come
run
run
swim swum
fly
flown
see
seen
speak spoken
do done
give
given
hide hidden
become become
take
taken
get gotten / got
break broken
shake shaken
wake
waken
awake awaken
rise risen
lay lain
fall fallen
begin begun
know known
forget
forgotten
write written
choose chosen
drink drunk
eat
eaten
bite bitten
show
shown
She has forgotten her name. She has amnesia.
她已经忘记了自己的名字。她有健忘症。
I have already drunk the coffee.
我已经喝过咖啡了。
They have gone to see the President.
他们已经去见校长了。
She has come to see you.
她来看过你了。
当have被用在现在完成时态中时，它可以和前面的代名词一起组成缩写形式。
I've been to New York once before.
我曾经到过纽约。
He's gone to the fish market.
他已经去过鱼市了。
We've come to help.
我们已经提供了帮助。
现在完成时用not来表达否定形式。当有not出现的时候，have可以和not组成缩写，但是此时不能和前面的代名词组成缩写。
She hasn't spoken to him.
她还没和他说过话。
We've not spoken with her.
提问的时候，have需要被提到句首。
Have you seen Matthew?
你见过马休了么？
简单过去时和现在完成时在一定程度上有共同之处，当然事实上两者之间有本质区别。当需要指明过去一个特定的时刻发生的事情时，需要使用简单过去式。
He finished three days ago.
他三天前做完了工作。
They finished a long time ago.
他们老早就完成工作了。
当没有特定指明的时间，现在完成时和简单过去时都可以使用。
I have already finished.
我早就完工了。
I already finished.
我早就完工了。
简单过去时比现在完成时更能表达事情的结果。
John has taught math for twenty years.
约翰已经教了20年的数学。
John taught math for twenty years.
约翰教了20年数学。
在上面的句子中，第一句保留了约翰继续教数学的可能性。第二句表明约翰已经不再教数学了，他可能退休了，换工作了，或者去世了。
Steve and Carol have eaten at that restaurant twice. They really like it.
史蒂文和卡洛尔已经在那家饭店吃过两次饭了。他们真的喜欢那里。
Steve and Carol ate at that restaurant twice.
史蒂文和卡洛尔两次在那家饭店吃饭。
如果一件事情发生在过去并且延续到说话的这个时刻，就需要使用现在完成时。
They have lived here for a long time.
他们在这里已经生活了很长一段时间。
She has been in Australia for two years.
她到澳大利亚已经两年了。
We have studied for 5 hours straight.
我们已经连续学习了5个小时。
Tim has waited for 30 minutes.
蒂姆已经等了30分钟了。
下面的句子包含了“动作在过去发生并且已经结束”的含义。
They lived here for a long time.
他们在这里住了很长一段时间
Melissa waited for 30 minutes.
梅丽莎等了30分钟。
通常当句子里有since时我们使用现在完成时。
We have lived here since June.
我们从六月份开始就住在这里。
She has been in China since last month.
她从上个月起就在中国了。
当现在完成时前有might时，就算主格是第三人称单数形式，我们还是使用have的动词原型形式。
She might have forgotten to lock the door.
她可能忘记了关门。
He might have given the painting to someone.
他可能已经把画给别人了。
Should、could、must没有简单过去时.他们用现在完成时来表达过去的状态。
He should have told you earlier.
他应该早点告诉你的。
I should have tried harder.
我应该更努力的。
She could have been nicer.
她可以做得更好的。
You must have seen him.
你一定已经见过他了。
My father has been working a lot.
我父亲已经做完了很多工作
We've been hiking in the mountains.
我们已经徒步旅行了许多山
I have been sleepy lately.
我睡得太晚了
She has been angry with me for as long as I can remember.
我能记得她已经很长时间在生我的气
Past Perfect 过去完成时
Richard had already left. I didn't see him.
理查德一定已经离开了.我没有看到他
They had eaten all the cookies. They didn't even leave a crumb.
他们把所有的饼干都吃完了,甚至连一点儿碎末都没留下
I had studied French, but I still couldn't understand him.
虽然我已经学过了法语,可到现在我还无法理解它
Future Perfect 将来完成时
By the time you get there, she will have already left.
当你到这儿时,她已经离开了
Conditional 条件句
Susan said that he would arrive soon.
苏珊说他不久便会到达
He thought that she would marry him.
他原想她会嫁给他
I hoped that you would at least try it.
我希望你至少要试试看
She would like to meet you.
想必她会很乐意见到你
I wish you would visit more often.
我希望你能常来这儿
Would可以与前面的代名词一起缩写变成 'd
I'd like some more coffee please.
我想要多一些咖啡
I knew that he'd do that.
我知道他会做这的
She'd rather be with me than you.
她觉得跟我在一起比跟你在一起更好
I'd have done the same thing.
我做了同样的事
Would同样用在过去式中
When I was a child, we would play cowboys and indian for hours.
当我还是个小孩儿时，我们一起晚牛仔与印地安人的游戏常常几个小时
When we were younger, we would swim accross the lake.
在我们更年轻时，我们可以游过湖对岸
Unreal Present 假设时态
If he was smart, he'd leave town right away.
如果他聪明的话，他早离开镇子了
If he became President, it would result in the destruction of the planet.
如果他成为总统，那便是世界末日了
If I was rich, I'd buy a ranch in Texas and raise cattle.
如果我很富有，我一定在田纳西买块大牧场放牛
If your father found out, he'd be really angry.
如果你父亲发现了，一定非常生气
If I had known, I would have helped.
如果我知道的话，我一定帮忙
If we had listened to our parents, we wouldn't be in this situation.
如果我们听从了父母的话，我们就不会陷入这种境地了
If I had known there were snakes in the water, I wouldn't have gotten in.
如果我知道那儿冬天有蛇，我就不会去了
If I had know about that, I never would have married him.
如果我知道那些事的话，我决不会嫁给他
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