定冠词the a an的用法？要详细完整!

不定冠词表示泛指，定冠词表示特指。
　　不定冠词a (an)与数词one 同源，是"一个"的意思。a用于辅音音素前，一般读作[e]，而an则用于元音音素前，一般读做[en]。
　　1) 表示"一个"，意为one；指某人或某物，意为a certain。
　　A Mr. Ling is waiting for you.

　　2) 代表一类人或物
　　A knife is a tool for cutting with.
　　Mr. Smith is an engineer.
　　定冠词the与指示代词this，that同源，有"那（这）个"的意思，但较弱，可以和一个名词连用，来表示某个或某些特定的人或东西。

　　定冠词的用法:
　　1）特指双方都明白的人或物：
　　Take the medicine. 把药吃了。
　　2）上文提到过的人或事：
　　He bought a house. I've been to the house.
　　他买了幢房子。我去过那幢房子。
　　3）指世上独一物二的事物：
　　the sun， the sky， the moon， the earth
　　4）单数名词连用表示一类事物，如：the dollar 美元;
　　the fox 狐狸；或与形容词或分词连用，表示一类人：the rich 富人; the living 生者。
　　5）用在序数词和形容词最高级，及形容词only， very， same等前面：
　　Where do you live? I live on the second floor. 你住在哪？我住在二层。
　　That's the very thing I've been looking for. 那正是我要找的东西。
　　6）与复数名词连用，指整个群体：
　　They are the teachers of this school.指全体教师)
　　They are teachers of this school. (指部分教师)
　　7）表示所有，相当于物主代词，用在表示身体部位的名词前：
　　She caught me by the arm.. 她抓住了我的手臂。
　　8）用在某些由普通名词构成的国家名称、机关团体、阶级、等专有名词前：
　　the People's Republic of China 中华人民共和国
　　the United States 美国
　　9）用在表示乐器的名词之前： She plays the piano. 她会弹钢琴。
　　10) 用在姓氏的复数名词之前，表示一家人：
　　the Greens 格林一家人 (或格林夫妇)
　　11) 用在惯用语中：
　　in the day, in the morning (afternoon，evening), the day after tomorrow
　　the day before yesterday, the next morning,
　　in the sky (water，field，country)
　　in the dark, in the rain, in the distance,
　　in the middle (of), in the end,
　　on the whole, by the way, go to the theatre
　　冠词口诀
　　冠词分为定冠、不定冠，
　　不定冠词a和an，“—”的含义表泛指
　　表示特指要用the，次序、方位、最高级
　　世上物体独一个，人或事物再次提
　　以下情况冠词免，学科球类三顿饭
　　名词复数表泛指，季节星期月份前

一、 不定冠词的用法
1)用与可数名词的单数形式前,指人或事物的某一种类：例如：
She is a girl.
Pass me an apple , please.
2)、指某人或某物,但不具体说明何人或何物。例如：
A boy is waiting for you
We work six days a week.
3). 表示 “一”这个数量,但数的概念没有one 强烈.例如:
We are going to have an English lesson tomorrow.
I have a mouth , a nose, two eyes and two ears.
4). 用于某些固定的词组中.例如:
a few, a little, a lot of,
注: 用a 还是an, 要看后面的词读音以辅音开头还是以元音开头.
二、定冠词的用法
1) 特指某(些)人或某(些)物.例如: the photo of the boy
2) 指双方都知道的人或物.例如:
-Where are the new books, Jim?
- They are on the small table.
3) 指上文提过的人或物.例如:
Today he is making a machine.
He wants to ride the machine like a bike and fly it like a plane.
4). 用在世界上独一无二的事物前.例如:
The sun is bigger than the moon.
5). 用在序数词或形容词最高级前.例如:
The first truck is carrying a few baskets.
The third one is carrying the fewest of all.
6). 用在由普通名词构成的专有名词前.例如:
the Great Wall
the North Street Hospital
7). 用在一些习惯用语中.例如:
in the morning (afternoon, evening),
on the left(right)
at the end of

三、不用冠词的情况
1）在专有名词前和不可数名词前。例如：
China, Grade Two, Bill Smith, milk
2）名词前已有作定语用的this, that, my, your, some, any 等代词。例如：
The letter is in her pocket.
I think the shop is closed at this time of day.
3）复数名词表示一类人或事物时。例如：
My father and mother are teachers.
I like cakes.

4）在星期、月份、季节、节日前。例如：
It is Sunday (Monday, Tuesday, etc.)
Today is Mid-Autumn Day.
It is cold in winter.
5）在称呼语或表示头衔的名词前。例如：
Uncle Wang likes making things.
What colour are Mrs Green’s shoes?
6）在三餐饭和球类运动的名称前。例如：
He went to school after breakfast.
Can you play basketball?

希望可以帮到你

The and a/an are called "articles"= 冠词

We divide them into "definite" and "indefinite" like this:
DEFINITE = SURE = 明确的；一定的；肯定；有把握 - PARTICULAR = 特别的；详细的；独有的
INDEFINITE = NOT SURE = 不明确的，模糊的 - GENERAL = 普遍的
THE IS DEFINITE .. A & AN ARE INDEFINITE
Think of the sky at night. In the sky we see 1 moon and millions of stars. So normally we would say:
I saw the moon last night.
I saw a star last night.
I AM ANSWERING THE QUESTION YOU ASKED - MENTIONING "THE QUESTION" - YOUR QUESTION .

Have you got a book - ( ANY BOOK, NOT MENTIONED WHICH BOOKS )
I WANT TO EAT AN APPLE ... ( ANY APPLE - NOT A PARTICULAR APPLE )