一个可以是a,元音字母前用an
例：This is an apple.
It's a ball.
only one 也可以表示唯一的一个,the 表示特指
例:You are the only one who really know me at all.
a few 与 a little 都表示肯定的意思，指“有一点，有一些”。a little加可数名词，a bit 加不可数名词
例： I bought a few newspapers.
There is a little ink in my pen.
I've got a bit of shopping to do.
some,a lot of ,a number of 也是一些，直接加名词。some用于肯定句
例：He gave me some good advice.
There are a lot of people.
A great number of studens are having class now.
any 用于否定句或者疑问句
例： Are there any biscuits on the desk ?
这些基本就够用了。
英语中单位，一台，一个，一片，一只，一套等的表达方式：
1、一台：a set of。
2、一个：one of。
3、一片：a piece of。
4、一只：a suit of。
表示：
1、一台电机：a set of electric motor。
2、一套配置：a set of configuration。
3、一只膨胀阀：a suit of expansion valve。
