知识要点：
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.
