1.world的基本意思是“世界,天下”,常与介词in连用,其前面可加不定冠词a。world也可指“天体,星球”,尤指可能有生物的星球,作这两种意思解时,可用作可数名词,也可用作不可数名词。
2.world可表示“范围,…界”; 也可表示“全世界的人,人类,公众,群众”,这时其前须加定冠词the; 还可表示“人世生活,世面,眼界,世俗”。作以上解时,常用作单数形式。world还可作“大量,无数”解。
3.in the world作强势语时用于以下结构中:①最高级结构; ②有only修饰的句子; ③用来修饰nothing。
4.world还可用于其他名词前作定语。

(all) the world and his wife
人人,许多人 many people
We went down town to do some Christmas shopping and all the world and his wife were there.我们去城市里购买圣诞用品,那里人山人海。
The world and his wife were in Brighton that day!那天在布赖顿市人山人海!

all the world to
对…至关重要 very important to
My family means all the world to me.对我来说,没有什么比我的家庭更重要。
I wouldn't hurt her feelings for the whole world.She's all the world to me.I'd give all the world to protect her.我无论如何不会伤害她的感情,她是我的一切,我愿付出一切来保护她。

for all the world as if〔like〕
正像…一样 exactly as if〔like〕
He goes round giving orders to everyone, for all the world as if he owns the company!他到处走来走去对大家发号施令,简直就像公司是他的一样!
He walked in out of the rain looking for all the world like a drowned rat.他从雨里走进来时看上去湿得完全像一只落汤鸡。

not for (all)the world
无论如何不,肯定不会 certainly not
I wouldn't hurt her for the world.我绝不会伤害她的。
I wouldn't do it for all the world.无论如何我都不干。
I wouldn't sell that picture for all the world.我无论如何也不卖那幅画。

out of this world
1.不切实际 unrealistic, impracticable
His idea is always out of this world.他的想法总是不切实际。
Don't be out of this world, you are only a student.实际点,你仅仅是个学生。
2.好得不得了 absolutely wonderful, magnificent, beautiful, etc.
The scenery and costumes for the opera are out of this world.这个歌剧的布景和戏装好极了。

set the world on fire
极为成功并引起轰动 be very successful and cause great excitement
She does the job adequately but she's not going to set the world on fire!她工作做得不错,但也不会有什么惊人之举!

what (who, why) in the world
到底是什么,究竟是什么 emphatically what, why, etc.
What in the world do you mean?你的意思到底是什么?
Why in the world did you marry him in the first place?首先你究竟为什么嫁给他?
Who in the world are you?你究竟是谁?

She has sailed round the world.她作过环球航行。
Our world is but a small part of the universe.我们的地球只不过是宇宙的一小部分。
Is there life on other worlds?其他星球上有生命吗?
Nine worlds go round our sun.九个行星围绕太阳运转。
Wilson conceived of a world free from war.威尔逊设想了一个摆脱战争的世界。
Some like security.Some like danger.It takes all sorts to make a world.有人喜欢安全,有人喜欢冒险,形形色色,构成世界。
You are a ray of light to me in a very dark world.你是我黑暗世界中的一束光线。
The women's volleyball team put up a desperate fight to win the world championship at all costs.女子排球队为争取世界冠军而不惜一切代价,殊死拼搏。
It is not easy to be in the commercial world.在商界是不容易的。
Politics was a man's world.政治是男人的世界。
He is known to the Western world.西方人,全世界人都知道他。
He retired to the country and shut out the world.他退隐到乡村而与人们隔绝。
The world goes very well with me.在世界大战期间全世界的人类都受了苦。
The world goes very well with me.我的情况很好。
You must see the world a lot.你应该多见见世面。
He is not of the world.他超然脱俗。
He's very young and inexperienced, and doesn't know about the ways of the world.他还很年轻,又缺乏经验,不懂得人情世故。
They met a world of trouble.他们遇到了许多困难。
There's a world of difference between thinking about it and doing it!这件事说是一回事,真的干起来是另一回事,两者相差太远。
I went to a world of trouble to help him, but it was all of no use.我千辛万苦地帮助他,可是全部白费了。
The ancient Egyptian civilization is one of the oldest in the world.古埃及文化是世界上最古老的文化之一。
Madame Curie was the only famous woman scientist in the world.居里夫人是世界上唯一有名的女科学家。
Nothing in the world can stop us going ahead.世界上没有什么东西能阻挡我们前进。

world, earth, globe
参见earth条。
下面三句意思相同,前两句意思更普通些:
My holiday did my health a world of good.
My holiday did my health the world of good.
My holiday did my health worlds of good.
我的假期对我的健康有很大的益处。
下面out of this world在句中的意思不同:
He is a very well-meaning person, but
he is out of this world.
他的用意相当好,可就是不切合实际。
The performance was simply out of this
world.
那场演出简直再好不过了。

1.中国是世界上人口最多的国家。
［误］  China is the country that has the largest population in world.
［正］  China is the country that has the largest population in the world.
［析］  world(世界)是独一无二的东西,前面要加定冠词the。同样,在sun, moon, earth, sky等名词前也要加the。
2.你究竟在哪里找到那顶帽子的?
［误］  Where in world did you find that hat?
［正］  Where in the world did you find that hat?
［析］  in the world表示“究竟”,是固定搭配,这里的the不能省去。

［同义词］   area, earth, field, globe, planet
［词源］  ＜古英语w(e)orold(世界,地球)