不定冠词:

不定冠词"a"用来表示可数名词的单数形式,用于辅音音素前,an用于元音音素前。
如:a person, a day, an hour, an old man...

定冠词用法:

1.用于双方都知道的名词前:Please clean the classroom.

2.用于单数名词前,表示一类人或物:
The horse is a useful animal.(马是有用的动物)
This is a very hard job for the teacher.(对于老师这是一项很难的工作。)

3.用于世界上独一无二的东西前:the sun, the spring.

4.用于方位名词前:People in the west like coffee very much.

5.用于乐器名词前:play the violin

6.用于计量单位前:Gasoline is sold by the gallon.

7.形容词最高级和序数词前:
This is the easiest way to work out the problem.
He came to see me for the first time.

8.用于江河湖海山脉名称前:the Pacific,the Thames,the Rocky Mountains

9.杂志、报刊名称前:the Times,the Overseas Digest

10.用于建筑物、和组织前:the White House, the Ministry of Education

11.用于姓氏复数前,表“某某夫妇,某某一家人:the Smiths,the Greens

12.用于形容词前,表一类人 / 物:the rich, the blind

13.用于 English,Chinese,French 等名词前,表“全体国民” :the English,the Chinese

以下情况不用冠词:

1.三餐前 breakfast,lunch,supper, ... Have you had lunch?

2.体育运动项目前 play chess,... I have no interest in tennis.

3.在由 by引出的交通工具前 by air(乘飞机),by car

4.在称呼或职位前 He has been elected president of the committee.

5.习惯用语前 at school,day by day,at table(在吃饭),go to church(做礼拜)...