A 一半的，半个的equal to either of two equal parts

　～ holiday　半日假
　～ a century　半个世纪
　～ a dozen　半打
　～ boots　半高筒靴
　～ knowledge　一知半解
　～ salary　半薪
　～ share　半份
　～ the number　半数
　～ the price　半价

　Half the apples are bad.　这些苹果有一半是坏的。
　They stood in half a circle.　他们站成半圆形。
　A half truth is often no better than a lie.　半真半假的话不见得比说谎要好。
　Half knowledge of anything is dangerous.　对任何东西一知半解都是危险的。
　My home is half a kilometer away from here.　我家离这儿有半公里。
　He went out at half nine.　他九点半以后出门。
　I met him half an hour ago.　我半小时前碰到他。

 ♣ half the battle
　成功的一半　the biggest part of the difficulty finished
　Persuading her it's a good idea is half the battle, once she's convinced, she'll do a good job.　说服她相信这是个好主意，成功就大有希望了，她一旦被说服，就会干得非常出色。

1. “一个半某物”有两种表达法：a/an+名词单数+and a half(half为名词）或one and a half+名词复数(half为形容词）。例如：
　A month and a half has passed.　一个半月过去了。
　One and a half pears is left on the table.　桌上还留一个半梨子。
　在上述两种结构作主语时，谓语动词都用单数形式。
2. half在表示“一半”的数量时，英式英语一般用half a/an，如half an hour（半小时）， half a dozen（半打）；而美式英语一般用a half，如a half hour, a half dozen, a half apple. 但half与数词连用时，冠词须置于half之前。例如：
　I spent two and a half years there.　我在那儿呆了两年半。

C 半，一半one of two equal parts

　Cut the apple into halves.　把这个苹果切成两半。
　He's in the bottom half of the class.　他在班上的名次位于后一半。
　The score of the first half was 2 to 1.　上半场的比分是2:1。
　Railway fares are reduced by half for children.　铁路旅费对儿童减半。
　Half of ten is five.　十的一半是五。
　Half of the apples are unripe.　一半的苹果不熟。
　Half of them are gone.　他们之中的一半人走了。
　Only half of us came last Tuesday.　上星期二我们只有一半人来了。
　She gave me half, and kept the other half for her husband.　她给了我一半，把另一半留给她的丈夫了。

 ♣ and a half
1. 质量上乘of very good quality
　That was a meal and a half!　吃了一顿比较好的饭菜！
2. 非同小可的，十分精彩of more than usual importance, excellence, size, etc.
　That was a game and a half!　那场比赛十分精彩！
 ♣ by halves
　部分地，不完全地　in part; incompletely
　I recommended that wine to him and he bought ten cases of it, he never does anything by halves.　我向他推荐那种酒，他买了十箱，他做事真是从不马虎。

 ♣ half, half of
　二者的共同意思是“一半”。
1. 前者的意思是“一半（量）的”，是形容词；后者的含意是“一半的量”，是量词。前者侧重于“物”；后者侧重于“量”。
2. 修饰名词时，用不用of均可，但在表示尺寸、数量的名词前，不可用of，在代词前一定要用of.
 ♣ by half, by halves
　前者的意思是“过分”，多半用于讽刺意味；后者的意思是“不完全地”，多半用于否定句中。试比较下列两个句子：

1. 一半　to the extent of half
2. 部分地　partly

　half　用作副词时的意思是“半”“部分地”，还可指同等程度的“一半…，一半…”。有时仅用来加强语气，无词意。

　He was half under the bed, with his legs sticking out.　他一半身子在床上，腿伸在外面。
　My work is not half done yet.　我的工作还没做完一半呢。
　These potatoes are only half cooked.　这些土豆煮得半生不熟。
　We were driving half when the car broke down.　当汽车抛锚时，我们正行驶了一半的路程。
　She was half laughing, half crying.　她半哭半笑。
　The boy was half dead from hunger.　那男孩由于饥饿已经半死不活的了。
　Oh, I'm half dead.　哦，我快累死了。

 ♣ not half
1. 一点也不not at all
　It's not half bad, your new flat.　你这套新公寓很不错。
2. 非常，极其the greatest possible extent
　It isn't half windy today!　今天风很大！
　He didn't half complain!　他很不满意！
 ♣ not half as
　远远不，几乎不　not nearly as
　I didn't feel half as cold once they'd put the heating on.　他们一打开暖气，我就几乎不觉得冷了。

　［同义词］ adj. divided, deficient, limited adv. partly, partially
　［反义词］ adj. all, total, whole adv. completely, entirely, wholly
　［词源］古英语healf（一半，部分，边）