1、特指某人或某物
例：This is the house which I lived in ten years ago.
2、用于第二次提到的人或物前
例：There is a boy on the playground. The boy is Tom.
3、用于自然界中独一无二的事物的名词前
例：The earth goes around the sun.
4、用在西洋乐器名词前
例：My sister enjoys playing the piano.
5、用在地理名词前，表示江、海洋、山脉、群岛、海峡、海湾
例：The Pacific is the largest ocean on earth.
6、用在序数词或形容词最高级前
例：Chinese is the most difficult language to learn.
7、用在某些固定搭配里面
例：all over the world, in the past, in the end, at the same time
练：
1、____Great Wall is one of the seven wonders around the world.
A. The
B. A
C. An
D./
2、There is ____ map of China on the wall in my bedroom.
A. a
B. an
C. the
3、Chinese learning is popular with people all over ____ world.
A. a
B. /
C. the
