1、定冠词的基本用法：

① 表示上文提到过的人或事物。如：i have bought a book. the book is very useful.

② 用于说话人与听话人心中都有数的人或事物。如：close the window, please.

③ 用于表示世界上独一无二的事物前。如：the sun, the moon, the earth, the world等。

④ 用于表示方位的名词之前。如：the east, the right.

⑤ 用于序数词或形容词的最高级之前。如：the first, the tallest.

⑥ 用于形容词之前，使其名词化。如：the sick, the wounded.

⑦ 用于由普通名词构成的专有名词之前。如：the united states, the united nation.

⑧ 用于江河、海洋、海峡、山脉、群岛、建筑物等的名词之前。如：the changjiang river, the east lake.

⑨ 用于复数姓氏之前，表示“夫妇”或“全家”。如：the smiths

⑩ 用于乐器的名词前。如：play the piano; play the violin.

⑾　发明物。如：the compass was invented in china. 

⑿　年代名词前。如：he lived in the countryside in the 1970s. 

　　⒀　固定词组中。如：in the morning(afternoon, evening), on the other hand , at the same time

2、不定冠词的基本用法：

① 泛指一个。如：there is a book on the table.

② 指人或事物的某一种类。如：his father is a driver.  longjing is a wonderful tea.

③ 指某一个人或事物，但不具体说明。如：my sister was saved by a pla man in the fire.

④ 用于某一些表示重量、长度、时间等单位前，表示“每一”。如：we have meals three times a day.（我们一天吃三餐。）

⑤ 表示同样的。如：they are of an age.（他们是同岁。）

⑥ 表数量，相当于one,但语意较弱。如：there is a pen and two books on the desk. 

　　⑦ 使抽象名词具体化。如：the little girl is a help to her mother. （a hand译"帮手"）

　　⑧ 固定搭配。如：as a matter of fact , in a hurry, in a word 

3、不用冠词的情况：

① 表示总称的复数名词之前。如：children love cartoons.（儿童喜欢卡通影片。）

② 不含普通名词的专有名词前。如：we are studying english.

③ 名词前有指示代词、物主代词、不定代词或名词所有格修饰时。如：i like this picture; i do not have any money; as time went on, einstein’s theory proved to be correct.

④ 季节、月份、星期等名词前，一般不用冠词。如：she likes spring most.

⑤ 呼语前不用冠词。如：what shall i do next, mother?

⑥ 三餐饭前不用冠词。如：what did you have for lunch?

⑦ 节假日前不用冠词。如：people give gifts to each other on christmas day.

⑧ 球类和棋类运动的名称前不用冠词。如：she is fond of playing basketball.

⑨ 在一些成对出现的短语中不用冠词。如：arm in arm（手挽手）; hand in hand（手牵手）; side by side（肩对肩）; day and day（日日夜夜）; young and old（老老少少）; from door to door（挨门挨户）; from beginning to end（从头到尾）; from morning till night（从早到晚）等。