不定冠词常位于名词或名词修饰语前。注意：

　　a. 位于下列形容词之后：such, what, many, half

　　I have never seen such an animal.

　　Many a man is fit for the job.

　　b. 当名词前的形容词被副词 as, so, too, how, however, enough 修饰时，不定冠词应放在形容词之后：

　　It is as pleasant a day as I have ever spent.

　　So short a time.

　　Too long a distance.

　　c. quite, rather 与单数名词连用，冠词放在其后。

　　但当 rather, quite 前仍有形容词，不定冠词放其前后均可。如：quite a lot