不定冠词 a/an的用法

　　a用于辅音音标开头的单词前(不一定是辅音字母)：an用于元音音标开头的单词前(不一定是元音字母) ：an old man

　　a friend

　　an American writer

　　a Chinese bookan English book

　　注意 以字母h，u，e，y开头的单词：an hour/honor/honest

　　a universityan umbrella-a usual/useful book

　　a European

　　a young mana youth

　　泛指人、事、物的类别 A.English is a useful language.

　　B.A horse is a useful animal.

　　C.His telehpone number begins with a " 3".

　　泛指某人某物

　　There‘s a man waiting for you at the gate of our school.

　　There‘s a book lying on the floor.

　　表示every/per的含义

　　This kind of Santana car can run 150 kilometers an hour.

　　Some students of Senior Three study 12 hours a day.