half

名词 half:

1. one of two equal parts of a divisible whole
   同义词：one-half
2. in various games or performances: either of two periods of play separated by an interval

形容词 half:

1. consisting of one of two equivalent parts in value or quantity
2. partial
3. (of siblings) related through one parent only

副词 half:

1. partially or to the extent of a half

1. The food's not half bad.
   这食物挺不错。
2. Half of them are here.
   半数人来了。
3. The girl left her homework half done.
   这女孩只做完了一半作业。
4. Half the car was damaged.
   车子毁了一半。

half

n.（名词）
【复数】 halves[h2vz, hôvz]
Abbr. hf.
缩写 hf.
One of two equal parts that together constitute a whole.
一半：一起组成一个整体的相等的两部分中的一个
One part approximately equal to the remaining part.
半部分：与余下的部分大致相当的部分
Informal A 50-cent piece.
【非正式用语】 一个50美分的硬币
Sports
【体育运动】
One of the two playing periods into which certain games are divided.
半场：某些体育比赛被划分成两个阶段，其中之一被称为半场
A halfback.
中卫
Chiefly British A school term; a semester.
【多用于英国】 半学年：学校术语；一学期
Half an hour:
半小时：
例句：
a half past one.
点半

adj.（形容词）
Abbr. hf.
缩写 hf.
Being one of two equal parts.
一半的：两个相等物之一的
Being approximately a half.
大约一半的
Partial or incomplete:
部分的，不完全的：
例句：
gave me a half smile.
对我似笑非笑

adv.（副词）
To the extent of exactly or nearly 50 percent:
大约一半地：正好或差不多达到百分之五十的程度：
例句：
The tank is half empty.
油箱是半空的

Not completely or sufficiently; partly:
不彻底地或不充分地；部分地：
例句：
only half right.
不完全正确

<习惯用语>by half
By a considerable extent.
以可观程度地
By an excessive amount:
过度地：
例句：
too clever by half.
过于聪明

by halves
In a reluctant manner; unenthusiastically.
不热情地：采取一种勉强的态度；不热情地
in half
Into halves.
成为相等的两半
not half
Not at all:
一点儿也不：
例句：
.Fancy housingô Not half likely, ma`am.(Russell Baker)
.上妓院ô根本不可能，女士.(拉塞尔·巴克)

not the half of
Only a fraction or a small part of.
只有一个片断或一小部分
来源：
Middle English
中古英语
from Old English healf * see skel-
源自 古英语 healf *参见 skel-

The phrasesa half, half of, and half a or half an are all correct, though they may differ slightly in meaning.For example,a half day is used when day has the special sense .a working day,. and the phrase then means .4 hours.. Half of a day and half a day are not restricted in this way and can mean either 4 or 2 hours.
短语a half，half of 和 half a 或者 half an 都是正确的， 尽管它们可能在意义上稍有不同。例如当day 当工作日来讲时， a half day 这个短语的意思是.四个小时.。 Half of a day 和 half a day 的意思不限于此， 它们可以表示四小时或者十二小时