1

指一類人或事，相當于a kind of

A plane is a machine that can fly.

2

第一次提及某人某物，非特指

A boy is waiting for you.

3

表示“每一”相當于every，one

We study eight hours a day.

4

表示“相同”相當于the same

We are nearly of an age.

5

用于人名前，表示不認識此人或與某名人有類似性質的人或事

A Mr. Smith came to visit you when you were out

That boy is rather a Lei Feng.

6

用于固定詞組中

A couple of, a bit, once upon a time, in a hurry, have a walk, many a time

7

用于quite, rather, many, half, what, such之后

This room is rather a big one.

8

用于so(as, too, how)+形容詞之后

She is as clever a girl as you can wish to meet.

1

表示某一類人或物

The horse is a useful animal.

2

用于世上獨一無二的事物名詞前

the universe, the moon, the Pacific Ocean

3

表示說話雙方都了解的或上文提到過的人或事

Would you mind opening the door?

4

用于樂器前面

play the violin, play the guitar

5

用于形容詞和分詞前表示一類人

the reach, the living, the wounded

6

表示“一家人”或“夫婦”

the Greens, the Wangs

7

用于序數(shù)詞和形容詞副詞比較級最高級前

He is the taller of the two children.

8

用于國家黨派等以及江河湖海，山川群島的名詞前

the United States, the Communist Party of China, the French

9

用于表示發(fā)明物的單數(shù)名詞前

The compass was invented in China.

10

在逢十的復數(shù)數(shù)詞之前，指世紀的某個年代

in the 1990’s

11

用于表示單位的名詞前

I hired the car by the hour.

12

用于方位名詞，身體部位名詞，及表示時間的詞組前

He patted me on the shoulder.

1

專有名詞，物質名詞，抽象名詞，人名地名等名詞前

Beijing University, Jack, China, love, air

2

名詞前有this, my, whose, some, no, each, every等限制

I want this book, not that one. /  Whose purse is this?

3

季節(jié)，月份，星期，節(jié)假日，一日三餐前

March, Sunday, National Day, spring

4

表示職位，身份，頭銜的名詞前

Lincoln was made President of America.

5

學科，語言，球類，棋類名詞前

He likes playing football/chess.

6

與by連用表示交通工具的名詞前

by train, by air, by land

7

以and連接的兩個相對的名詞并用時

husband and wife, knife and fork, day and night

8

表示泛指的復數(shù)名詞前

Horses are useful animals.