不定冠詞“a”用來表示可數(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, anold man...
I．定冠詞用法如下：
（英語剛啟蒙時(shí)你就知道冠詞了，可你真正掌握了嗎？再背一遍又何妨？?。?1．用于雙方都知道的名詞前：Please cleanthe classroom．
2．用于單數(shù)名詞前，表示一類人或物：
The horseis a useful animal.（馬是有用的動(dòng)物）
This is a very hardjob for theteacher.（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．用于樂器名詞前：play the violin.
6．用于計(jì)量單位前：Gasoline is soldby 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 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, theMinistry 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, theblind
13．用于 English，Chinese，F(xiàn)rench等名詞前，表“全體國(guó)民”the English，the Chinese
II．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 playchess，... I have nointerest intennis.
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)慣用語前 at school，day by day，at table（在吃飯），go to church（做禮拜）...