1

指一类人或事，相当于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”相当于every，one

We study eight hours a day.

4

表示“相同”相当于the same

We are nearly of an age.

5

用于人名前，表示不认识此人或与某名人有类似性质的人或事

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

That boy is rather a Lei Feng.

6

用于固定词组中

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)+形容词之后

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

1

表示某一类人或物

The horse is a useful animal.

2

用于世上独一无二的事物名词前

the universe, the moon, the Pacific Ocean

3

表示说话双方都了解的或上文提到过的人或事

Would you mind opening the door?

4

用于乐器前面

play the violin, play the guitar

5

用于形容词和分词前表示一类人

the reach, the living, the wounded

6

表示“一家人”或“夫妇”

the Greens, the Wangs

7

用于序数词和形容词副词比较级最高级前

He is the taller of the two children.

8

用于国家党派等以及江河湖海，山川群岛的名词前

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

9

用于表示发明物的单数名词前

The compass was invented in China.

10

在逢十的复数数词之前，指世纪的某个年代

in the 1990’s

11

用于表示单位的名词前

I hired the car by the hour.

12

用于方位名词，身体部位名词，及表示时间的词组前

He patted me on the shoulder.

1

专有名词，物质名词，抽象名词，人名地名等名词前

Beijing University, Jack, China, love, air

2

名词前有this, my, whose, some, no, each, every等限制

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

3

季节，月份，星期，节假日，一日三餐前

March, Sunday, National Day, spring

4

表示职位，身份，头衔的名词前

Lincoln was made President of America.

5

学科，语言，球类，棋类名词前

He likes playing football/chess.

6

与by连用表示交通工具的名词前

by train, by air, by land

7

以and连接的两个相对的名词并用时

husband and wife, knife and fork, day and night

8

表示泛指的复数名词前

Horses are useful animals.