冠词是一种虚词，放在名词的前面，帮助说明名词的含义。冠词分不定冠词（The Indefinite Article）和定冠词（The definite Article）两种。a (an) 是不定冠词，a用在辅音之前：如a book, a man; an用在元音之前，如：an old man, an hour, an interesting book等。the是定冠词。
一、不定冠词的用法
1、指人或事物的某一种类（泛指）。这是不定冠词a (an)的基本用法。如：She is a girl. I am a teacher. Please pass me an apple.
2、指某人或某物，但不具体说明何人或何物。如：He borrowed a story-book from the library.
A Wang is looking for you. 一位姓王的同志正在找你。
3、表示数量，有“一”的意思，但数的概念没有one强烈。如：
I have a mouth, a nose and two eyes.
4、用于某些固定词组中。如：a bit, a few, a little, a lot of, a piece of, a cup of, a glass of, a pile of, a pair of, have a good time, for a while, for a long time等。
5、用在抽象名词前，表具体的介绍——a + 抽象名词，起具体化的作用。如：
This little girl is a joy to her parents. 这女孩对她父母来说是一个乐趣。
It is a pleasure to talk with you. 跟您交谈真是一件愉快的事情。
It is an honour to me to attend the meeting. 参加这个会，对我来说是一种荣誉。
二、定冠词的用法：
1、特指某（些）人或某（些）事物。这是定冠词the的基本用法。如：
Beijing is the capital of China.
The pen on the desk is mine.
2、指谈话双方都知道的人或事物。如：
Where is the teacher?
Open the window, please.
3、指上文提过的人或事物（第二次出现）。如：
There was a chair by the window. On the chair sat a young woman with a baby in her arms.
The baby was thin.
4、用在世界上独一无二的事物前。如：the earth, the moon, the sun。
5、用在序数词和形容词最高级前。（副词最高级前的定冠词可省略）如：
He is always the first to come to school.
Bob is the tallest in his class.
6、用在某些专有名词前（由普通名词构成的专用名词）。如：the Great Wall, the Summer Palace, the Science Museum, the Children’s Palace, the Party等。
7、用在一些习惯用语中。如：on the day, in the morning (afternoon, evening), the day after tomorrow, the day before yesterday, the next year, by the way等。
8、用在江河湖海、山脉前。如：the Yellow River, the Pacific Ocean, the Alps, the Himalayas
9、用在报刊、杂志前。如：the People’s Daily, the Evening Paper, the Times 泰晤士报
10、表示某一家人要加定冠词。如：
The Browns are at home to receive visitors today. 布朗一家今天要接待客人。
11、用在形容词前，表某一类人。如：the poor, the wounded, the living, the dead, the rich, the sick等。
12、定冠词可以表示一事物内部的某处。如：
The driver always sits in the front of the bus(car).
三、零冠词（即不用冠词）：
1、专用名词和不可数名词前。如：China, America, Grade One, Class Two, milk, oil, water, paper, science等。
2、名词前已有作定语用的this, that, my, your, some, any等代词。如：
Go down this street.
3、复数名词表示一类人或事物时。如：
We are students. I like reading stories.
4、节日、日期、月份、季节前。如：Teachers’ Day, Children’s Day, National Day, in summer, in July等。
Today is New Year’s Day. It is Sunday. March 8 is Women’s Day.
5、在称呼语或表示头衔的名词前，尤其作表语、宾补时。如：
What’s the matter, Granny? We elected him monitor.
6、在某些习惯用语中的名词前。如：at noon, at night, at first, at last, at most, at least, by bus(train, air, sea), in bed, in time, in front of, go to school, go to bed, go to college, on foot, at table, in ink, in pencil等。
7、在三餐饭和球类运动前。如：
She goes to school after breakfast every morning.
We are going to play football.
We usually have lunch at school.
8、科目前不加。如：
We learn Chinese, maths, English and some other subjects.
【专项训练】
1、We can’t live without ______ air.
A．an B．× C．the D．some
2、——Have you seen ______ pen? I left it here this morning.
——Is it ______ black one? I think I saw it somewhere.
A．a; the B．the; the C．the; a D．a; a
3、I’ve been waiting for him for ______ hour and ______ half.
A．×; × B．the; a C．a; the D．an; a
4、What ______ fine weather we have today!
A．a B．× C．some D．an
5、Have you ever seen ______ as tall as this one?
A．a tree B．such tree C．an tree D．tree
6、Children usually go to ______ school at ______ age of six.
A．×; the B．a; an C．the; × D．the; the
7、______ Himalayas is ______ highest mountain in ______ world.
A．×; the;× B．The; the; the C．A; a; a D．×;×;×
8、They each have ______ book. Li Hua’s is about ______ writer. Wang Lin’s is on ______ science.
A．a; a; × B．the; ×; the C．×; the; × D．a; the; a
9、______ Physics is ______ science of matter and energy.
A．The; × B．×; × C．×; the D．A; a
10、______ sun rises in ______ east and sets in ______ west.
A．A; an; a B．The;×;× C．The; the; the D．A; the; a