不定冠詞"a"用來(lái)表示可數(shù)名詞的單數(shù)形式，用于輔音音素前，an用于元音音素前。 如：a person, a day, an hour, an old man...

定冠詞用法：

1．用于雙方都知道的名詞前：Please clean the classroom.

2．用于單數(shù)名詞前，表示一類人或物： The horse is a useful animal.（馬是有用的動(dòng)物） This is a very hard job for the teacher.（對(duì)于老師這是一項(xiàng)很難的工作。）

3．用于世界上獨(dú)一無(wú)二的東西前：the sun, the spring.

4．用于方位名詞前：People in the west like coffee very much.

5．用于樂(lè)器名詞前：play the violin

6．用于計(jì)量單位前：Gasoline is sold by the gallon.

7．形容詞級(jí)和序數(shù)詞前： This is the easiest way to work out the problem. He came to see me for the first time.

8．用于江河湖海山脈名稱前：the Pacific，the Thames，the Rocky Mountains

9．雜志、報(bào)刊名稱前：the Times，the Overseas Digest

10．用于建筑物、和組織前：the White House, the Ministry of Education

11．用于姓氏復(fù)數(shù)前，表“某某夫婦，某某一家人：the Smiths，the Greens

12．用于形容詞前，表一類人 / 物：the rich, the blind

13．用于 English，Chinese，F(xiàn)rench 等名詞前，表“全體國(guó)民” ：the English，the Chinese

以下情況不用冠詞：

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

2．體育運(yùn)動(dòng)項(xiàng)目前 play chess,... I have no interest in tennis.

3．在由 by引出的交通工具前 by air（乘飛機(jī)），by car

4．在稱呼或職位前 He has been elected president of the committee.

5．習(xí)慣用語(yǔ)前 at school，day by day，at table（在吃飯），go to church（做禮拜）...