分配限定词 half 用来谈论一个划分为二的群体，在用作分配词的形式有很多种。其它部分也可以用于相同的形式，只是较为少见。
half 后可以接不定冠词（a 或 an）为首的测量单位，在这种用法上，分配限定词为一种测量法。
- I had half a cup of milk left.
- I bought half a kilo of flour.
- He ran half a mile this morning.
- I will be back in half a minute.
half 可以接名词，但两者之中必须夹带定冠词丶不定冠词丶指示代词或所有格代词。在这种情况下，它指的是一个具体丶实质上的划分。而 half 接 of 并不会改变意思。
- Half the people have already left.
- Half of an apple isn't very much lunch.
- Did you use half my sugar?
- I will need half of the flour for my cake.
- I earned half of that money last summer.
- She found half these frogs in the river.
- I spent half that time on my project.
- You can take half of those books back.
- I've invited half my friends to the party.
- I've used up half of our eggs.
- You wasted half your money on that!
half 后可以接 of + 复数代词。
- Half of us are going.
- He scolded half of you but he let the rest off.
- You couldn't find half of them?