二.冠词：不定冠词，定冠词种类：
(1)不定冠词：a / an
元音开头的可数名词前用an :
an egg / an apple / an orange / an eraser / an answer / an ID card / an alarm clock / an actor / an actress / an e-mail / an address / an event / an example / an opera / an houran old man / an interesting book / an exciting sport / an action movie / an art lesson /
(2)定冠词：the
定冠词的用法：
(1)特指某(些)人或某(些)物：The ruler is on the desk.
(2)复述上文提到的人或物：He has a sweater. The sweater is new.
(3)谈话双方都知道的人或物：The boys aren’t at school.
(4)在序数词前：John’s birthday is February the second.
(5)用于固定词组中：in the morning / afternoon / evening
不用冠词的情况：
(1)专有名词前：China is a big country.
(2)名词前有定语：this , that , my , your , some, any , no 等：
This is my baseball.
(3)复数名词表示一类人和事：Monkeys can’t swim. They are teachers.
(4)在节日，日期，月份，季节前：Today is Christmas Day. It’s Sunday.
(5)一日三餐前：We have breakfast at 6:30.
(6)球类 棋类运动前：They often play football after class. He plays chess at home.
* 但乐器前要用定冠词：I play the guitar very well.
(7)学科名称前：My favorite subject is music.
(8)在称呼或头衔的名词前：This is Mr Li.
(9)固定词组中：at noon at night by bus
