本文就来谈谈不定冠词(indefinite articles) a/an 的用法。

　　不定冠词最基本的用途就是用来表示“一”这概念，如：

　　① A stitch in time saves nine.

　　② Jason is an internationally known scholar.

　　此外，a/an 还有下列 6 种用途：

　　㈠常和time、measurement等有关的名词连用，以表示“每—” 的概念，如：

　　③ I teach five days a week.

　　④ This type of vegetables is sold at one dollar a kilo.

　　⑤ My car usually runs sixty kilometres an hour.

　　㈡常和 hundred, thousand, dozen 以及数目及数量连用，如：

　　⑥ That factory turns out at least a hundred tyres a day.

　　⑦ Noel's monthly salary is a thousand dollars.

　　⑧ I have a number of sponsored students.

　　⑨ Mary has a lot of money.

　　㈢在“of / at”后面出现，以表示“同一类”这概念，如：

　　⑩ Birds of a feather flock together.

　　11. Please come one at a time.

　　12. Things of a kind come together, so do people of a mind.