1） 不定冠词的位置

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[1][2]