1.可数名词单数第一次提到（泛指）；She is working in a factory.
2.表示"某一个"的意思；A gentleman wants to see you.
表示“一”的概念 3.表示"同一"的意思；a.They are nearly of an age. b.The two shirts are much of a size.
4.表示"每一"的意思；We go swimming four times a week.
5.用在序数词前，表示“又一、再一”的含义；When I sat down, a fourth man stood up to speak.
6.用在表示世界上独一无二有形容词修饰的名词前；Everybody wishes to live in a peaceful world.
1.用于人名前，表示说话者对此人不认识或者表示与某名人有类似性质的人或者事物；A Smith is asking for you outside.
表示“一类”的概念
2.用在具体化的抽象名词前，表示“一个人”或“一件事”；My family is a failure in life.
不定冠词（a/an）
当表示“季节、月份、日期、三餐”的名词前有形容词修饰时；We really had a wonderful breakfast this morning.
用在作表语的单数可数名词前，表示身份、职业；My mother is a teacher.
冠词 有些不可数名词，如knowledge, collection, understanding后面加of时，前面需用不定冠词a/an；Her new book is a collection of short stories.
2.half/many/quite/rather/such+a/an+adj.+可数名词单数；We have never seen such a beautiful girl before.
3.表示“许多，大量” 修饰不可数名词：a great deal of；a large amount of；quite a little
既可以修饰可数名词也可以修饰不可数名词：a lot of; lots of；a large quantity of；a large supply of；a mass of；a pile of
4.其他的固定搭配：have a cold；have a fever；all of a sudden；in a hurry；for a while；in a word；have a gift for；have a word with；at a loss；once upon a time
1.表示宇宙中世界上独一无二的事物；the sun；the moon；the earth；the sky；the world；the internet；但space前没有冠词
2.在姓氏复述前，表示一家人；The Bakers came to see me yesterday.
3.用在序数词、形容词最高级以及形容词only, very, same前面；a.January is the first month of the year. b.Shanghai is the biggest city in
4.用以特指某（些）人或某（些）事物；This is the house where Luxun once lived.
5.用于指谈话双方都明确所指的人或事物，.特指双方都明白的人或者事物；a.Take the medicine. b.Open the door, please.
6.用以复述上文提过的人或事物（第一次提到用“a或an”，以后再次提到用“the”），指上文提到过的人或者事物；
a.He bought a house. I’ve been to the house. b.Once there lived a lion in the forest. Every day the lion asked small animals to look for food for him.
7.与形容词或分词连用，表示一类人或者一类事物；the rich, the wounded, the new
定冠词（the） 8.用在表示乐器的名词前，但中国乐器前没有定冠词；play the piano, play erhu
9.用在年代、朝代名词前或用在世纪或逢10的复数年代前；a.in one’s 50s b.A great many important events took place in the 1900s. c.The Tang Dynasty
10.用在表示计量单位的名词前；Apples are sold by the kilogram.但如果是单位名词的总称，名词前不用冠词；by weight；by time；by length；Fruit is sold by weight.
11.用在发明物的单数名词前，既表示特指又表示类别；Bell invented the telephone in 1876. the+n（发明物）必须是单数；
12.动词+sb.+介词+the +身体的某一部位；a.take sb. by the arm b.hit sb. in the face
13.指由普通名词构成的专有名词；the West Lake；the Great Wall；the United States；the United Nations
14.在海洋、江河、湖泊、山脉、海峡、海湾等地理名词前；the Pacific Ocean；the Huanghe River；the Tianshan Mountains；the Taiwan Straits
15.用在表示阶级、政党的名词前；the working class；the Chinese Communist Party
16.在the more, the more比较级的句式中；The more you drink, the more you like it.
17.固定搭配；in the morning；in the afternoon；in the evening；go to the cinema；go to the theatre；all the year round；on the way to
2.月、季、星期、节假、洲；呼语、头衔、职务前；三餐、球类，惯用语；学科、棋类名词前用零冠词；
a.He has no lessons on Sundays. b.It is usually very cold in winter in the north.
(表示呼语、头衔的名词做表语、同位语、补足语时用零冠词)，注意：如果表示“某个”应用不定冠词；表示特指应用定冠词。
a.I am not exactly sure when he returned but I’m sure that he returned on a Monday. b.The winter of last year was extremely cold.
3.专有名词前不加冠词；China；Europe；Lei Feng；William Shakespeare；Mount Qomolangma
零冠词（/） 4.in+书写工具或者颜料；You can never write your composition in red.
5.在独立主格结构中“名词+介词+名词”中的名词前；The teacher is standing in the front of the classroom, book in hand.
6.turn, go做系动词，表示“变为、成为” 时，后接可数名词单数做表语，不定冠词要省略；a.She turned teacher ten years ago. =she became a teacher ten years ago.
7.“零冠词+单数名词+as/though+主语+谓语”表示“虽然/尽管……，但是……”；Hero as he is, he has some shortcomings.
8.在"kind of＋名词 sort of＋名词"句式中；a.What kind of flower is it? b.I like this sort of book.
9.固定短语； at home；at first；on condition that；in charge of；in danger；in spite of；out of breath.
