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.