不定冠词a,an用法:
1 a 放在以辅音开头单词前,an放在以元音开头单词前，后接单数可数名词，表示一个(件，位……)
This is ( ) book.
I have ( ) apple.
2 用在固定短语中(惯用法)
There are ( ) lot of apples in the box.
3 用在文章中靠前次出现的单数的人或
物前
Long long ago, there lived ( ) old king.
定冠词 the 的用法:
1 表示特指
( ) cellphone I bought last Sunday is lost.
2.谈话双方都知道的人或物
Close ( ) door, please!
3 用在专有名词前
Have you ever been to ( ) Great Wall?。
