1. 不定冠词

(1)不定冠词的用法
①泛指—类人或物。
eg.This is a pencil case.
She's a doctor.
②指不具体的某个人或物。
eg.I met an old man On my way home.
③用在序数词前，相当于another。
eg.There's a third boy near the shop.
④表示“每—(个)”，相当于every。
eg.They have music lessons twice a week.
⑤固定搭配。
a lot of，a lot，a little，a few，a glass Of，such a/an，have a word with，have a look，have a try，have a swim，a quarter，half an hour，three times a day，have a talk，give a talk，ten Yuan a kilo
(2)不定冠词的位置
①不定冠词—般放在所修饰的单数可数名词前。
eg. bike，an egg
②当名词被such，what，many修饰时，不定冠词放在这些词之后。
eg.It took me half an hour to finish my homework.
He left in such a hurry that he forgot to close the door.
What a dangerous job it is!
Many a man has gone to the big cities for work.
③当名词前的形容词前有so，how，too等词时，不定冠词应放在形容词之后。
eg. She was so nice a girl that she took the　blind man to the station.
How nice a film this is!
④当名词前面有形容词和quite，rather，very时，不定冠词放在quite，rather之后，very之前。
eg.It is quite a good book.
That is rather a useful too1.
This is a very interesting story.