1. A person or thing specifically referred to
Example:
Please hand me the key on the desk. 请把桌上的钥匙递给我.
The girl in red is his sister. 穿红色衣服的女孩是他妹妹.
The building over there is the tallest in the town. 那边那幢大楼是这个城里最高的.
2. Indicates a person or thing that both parties know
Example:
Shut the door, please. 请关门.
Has he returned the book? 那本书他还了吗?
Take the blue one, it is cheaper. 拿那个蓝的,它便宜些.
Take the boy to the teachers’office,please.
3. When a person or thing is mentioned above, it is mentioned later.
Example:
He saw a house in the distance. Jim's parents lived in the house. 他看见远处有一所房子,吉姆的父母就住在那所房子里.
There was once an old fisherman. The old fisherman had a cat. The cat was white. 从前有一个老渔夫.这个老渔夫有一只猫.这只猫是只白猫.
4. In front of something unique in the world.
Such words are:
the sun太阳, the earth地球, the moon月亮, the sky天空, the world 世界
As long as such a word appears in the text, it must be preceded by the. Except in exceptional circumstances.
There is only one earth in the space.太空中只有一个地球。
5. It is used before the name of the direction and direction
Such words are:
the east东方,the west西方,the south南方,the north北方,the right右边,the left左边
Example:
The birds are flying to the north. 这些鸟向北方飞去.
The moon rises in the east and sets in the west. 月亮从东方升起,在西方落下.
The wind was blowing from the south. 风从南方吹来.
She lived to the west of the Summer Palace. 她住在颐和园的西边.
Walk along the road and take the first turning on the right. 沿着这条路往前走,在第一个路口往右拐.
He stood at the back of the door. 他站在门背后.
*Note: When the directional words are used in pairs to form a parallel structure, the definite article is not used.
Example:
The river is two thousand kilometers long from west to east. 这条河自西向2000公里长.
They traveled through the country from south to north. 他们自南向北在这个国家旅行.
6、形容词最高级前用the
例：Summer is the hottest season of the year. 夏天是一年中最炎热的季节.
She is the best person for the job. 她是最适合这个工作的人.
The car is the most expensive of the four. 这部车是四部车中最贵的.
7、序数词前用the
The definite article is used before ordinal numerals, before next, last, etc., and before words that indicate "same" or "unique", etc.
Example:
The first man to land on the moon is an American. 第一个登上月球的人是美国人.
She was the fifth to climb to the top of the mountain. 她是第五个到达山顶的人.
This may be the last chance. 这可能是最后一次机会.
If I miss this train I'll catch the next one. 如果赶不上这趟火车,我就赶下一趟.
*prompt
a) When an ordinal numer indicates "another", the indefinite article a(an) is preceded by an indefinite numeral
例：He bought a second pair of shoes. 他又买了一双鞋.
He asked a question, then a second, then a third… 他问了一个问题,又问了第二个,第三个……
b) When an ordinal number is used as an adverbial or predicate, it is not preceded by a definite article.
例：George arrived first. 乔治第一个到.
=George was the first person to arrive.
Jim and Jack are both second in the match. 汤姆和杰克在比赛中并列第二.
8. It is used before a singular noun to indicate a class of people or things, emphasizing the entire category
Example:
The orange is a kind of fruit. 橘子是一种水果.
The horse is a useful animal. 马是一种有用的动物.
The computer is important to us. 电脑对我们来说是重要的.
*Hint: Indefinite articles + singular nouns, plural nouns without articles can also indicate a class of people or things. When representing a class of people or things, a or an is used more often.
Example:
A car runs faster than a bus. 小汽车比公交车跑得快.
Cars run faster than buses.
A dog is a faithful animal. 狗是忠实的动物.
9. Before the noun of the instrument, it means to play
Example:
She can play the piano. 她会弹钢琴.
He plays the violin very well. 他小提琴拉得很好.
He played the guitar for the children. 他给孩子们弹了吉他.
*Note: However, when the instrument noun indicates a specific utensil, or indicates a lesson, it is not added.
Example:
He bought a piano last month. 他上个月买了一架钢琴.
She taught piano in the school. 她在学校里教钢琴.
10. It is used in front of the name of a river, ocean, lake, archipelago, mountain range, etc
Example:
the Yangtze River 长江
the Red Sea 红海
the West Lake 西湖
the Pacific 太平洋the Himalayas 喜马拉雅山
the Nile 尼罗河
the Rocky Mountains 落基山脉
the South China Sea 南中国海
*Note: Exception: Mount Tai China Daily
11. It is used before a proper noun composed of a common name
Example:
the Great Wall 长城
the United Nations 联合国
the New York Times 《纽约时报》
the United States of America 美国
the Red Cross Hospital 红十字医院the Olympic Games 奥林匹克运动会
the Shanghai Railway Station 上海火车站
the People's Republic of China 中华人民共和国
the North Pole 北极
the People's Daily 《人民日报》
12. It is used before certain adjectives to indicate a class of people or things
Example:
the old
the happy 幸福的人
the poor 穷人
the aged 老人
the sick 病人
the impossible 不可能的事the young 年轻人
the rich 富人
the blind 盲人
the wounded 伤员
the smooth 顺事
the beautiful 美,美的东西
例:
The rich should help the poor. 富人应该帮助穷人.
The good is what people like. 人们总是喜欢美好的东西.
The wounded have been sent to the hospital. 伤员已经被送到医院去了.
13. It is used before the plural form of the surname to indicate the whole family or the couple with this surname
Example:
The Greens will more to the country. 格林一家要搬到乡下去.
The Wangs came to see us yesterday. 王家一家人昨天来看我们.
The Browns are very friendly. 布朗夫妇都很友好.
14. It is used before the noun to indicate the unit of calculation, and contains the meaning of "every, every".
Example:
Jim is paid by the hour. 吉姆的工资按小时付.
Eggs are sold by the kilogram. 鸡蛋按千克出售.
This cloth is sold by the yard. 这种布按码出售.
It sells at three dollars the pound. 它以每磅三美元出售.
15. It is used in front of the noun of the body part or clothing of the person mentioned earlier
This usage is to speak of the whole object first, and then to the part of the subject's body or clothing.
结构：动词(hit, pull, pat, catch, hold, take)+sb.+介词(in, on, by, across)+身体部位或衣着
Example:
She touched him on the shoulder. 她碰了碰他的肩.
He took the girl by the hand. 他拉着小女孩的手.
He hit her on the nose. 他打了她的鼻子.
The stone struck the man in the eye. 石头击中了那人的眼睛.
I caught her by the right hand. 我抓住她的右手.
Comparison: She patted the boy on the head.
She patted the boy on his head. （误,本结构中身体部位或衣着前不用one's）
She patted the boy on the head. （正）
16. It is used before the plural number word every ten, indicating the age, and also referring to the approximate age of the person.
Example:
The war broke out in the forties. 那场战争发生在40年代.
He went abroad in the 1980s. 他在20世纪80年代出国的.
The old man is in the seventies. 老人大约七十几岁.
17. Used before a noun that denotes a natural phenomenon
Such terms are:
the rain 雨,the wind风, the fog雾,the snow雪, the air空气, the storm风暴,the snowstorm 暴风雪
Example:
Don't stand in the rain. 不要站在雨中.
The wind blew down the trees. 风把树刮倒了.
The rain has cleaned the air. 下雨净洁了空气.
The fog was so thick that we couldn't see the top of the hill. 雾很大,我们看不见山顶.
Prompt:
a) When such nouns are preceded by adjectives, an indefinite article can be used to mean "a, a, a"
例：A cold wind is blowing from the north. 冷风从北方吹来.
There was a heavy rain last night. 昨晚下了一场大雨.
A heavy snow is falling outside. 外面正下着大雪.
b) This type of noun does not use an article when it denotes a substance in general.
例：Rain falls in summer; snow falls in winter. 夏天下雨,冬天下雪.
Man can't live without air. 没有空气人不能活.
18. Used in conjunction with plural nouns, it refers to the whole group
例:
They are the teachers of this school.指全体教师。
19) means all, which is equivalent to the owner pronoun, which is used before the noun that indicates a body part
She caught me by the arm. 她抓住了我的手臂。
20. Used in some idiomatic expressions
Example:
in the morning 在上午
in the evening 在晚上
in the field 在田野里
in the country 在乡间
in the sun 在阳光下
in the distance 在远处
on the right 在右边
by the way 顺便说一下
in the front of 在前部
in the daytime 白天
go to the concert 去听音乐会
at (/in) the beginning 开始
at the moment 当时,此刻
all the year round 一年到头
go to the cinema 去看电影
go to the theatre 去看戏
at the weekend 周末
in the afternoon 在下午
in the night 在夜里
in the sky 在空中
in the dark 在暗处
in the rain 在雨中
in the shade 在阴凉处
on the left 在左边
all the time 始终
in the middle of 在中间
on the way home 回家途中
all the same 依然
on the whole 总之
at the same time 同时
on the plane 在飞机上
in the year 2008 在2008年
the other day 前几天
at the bottom of 在…… 底部
in the end 终于
on the one hand, on the other hand 一方面,另一方面
*Hint: The following phrases are not preceded by a definite article:
Example:
at dawn
at night at night
at noon at noon
When memorizing these usages, you should be flexible and not rigid. Only by learning and applying can we learn the true meaning.