摘要：用在表示时间、长度、重量等意义的名词前，相当于each 或per。
不定冠词a/an的用法总结
表示数量“一”a/an用于表示数量“一”，但不强调数量；
one强调数量，表示“一个”，而不是“两个”或“三个”。
eg: It has a mouth,a nose and two eyes.
它有一张嘴，一个鼻子和两只眼睛。
2.表示“一类”
eg: A bird can fly. 鸟会飞。
3.表示“某一个，某位”
eg:
I want to be a Yuan Longping when I grow up.
当我长大后，我想成为袁隆平那样的人。
A Mr.Li is asking to see you.
有位李先生要求见你。
4.表示“再一，又一”
eg:
The apple is delicious, and I would like a second one.
苹果很好吃，我想再吃一个。
He has failed three times. He wants to try a fourth time.
他已经失败了三次。他想再试一次。
5.表示“同一，相同”
eg:
The children are of an age.
这些孩子同龄。
6.表示“每一”
用在表示时间、长度、重量等意义的名词前，相当于each 或per。
eg: We usually have three meals a day.
我们通常每天吃三顿饭。
7.表示一个集体
eg：This is a family of eight.
这是八口之家。
8.表示“一，这种”
用在抽象名词之前，使抽象名词具象化，表示具体的人或事等。
eg: I am quite at a loss.
我不知所措。
9.表示“一阵，一份，一场”
用于某些物质名词之前。
eg: I'd like an ice cream.我想要一份冰激凌。
A heavy rain stopped us from going outside.
一场大雨阻止了我们外出。
常见的含不定冠词的短语
after a while 过了一会
I turned back after a while, but he kept walking 我过了一会就往回走了，但他还接着走。
in a hurry匆忙
I'm not getting married in a hurry ─ I'm waiting for Mr Right to come along. 我不想匆忙结婚——我在等着如意郎君的出现。
once upon a time从前
Once upon a time, there was a man called Zheng. 从前,有一个人叫郑。
do sb. a favour帮助某人
Will you please do me a favour [ give me a hand]?
劳你帮个忙。
have a cold感冒
I have a cold, but the doctor says I'll be as right as rain. be rained off.
我感冒了，但医生说我很快就能好。
make a face做鬼脸
Why do you make a face?
你为什么要做鬼脸？
as a whole总体上
As a whole we do not eat enough fibre in Britain.
总体上我们英国人没有摄入足够的膳食纤维。
in a word总之
In a word, he tires of everything.
简言之，他对一切都感到厌倦了。
with a smile微笑着
he greeted us with a smile.
她微笑着向我们打招呼。
give sb. a hand帮助某人
Come and give me a hand in the garden
到花园里来帮我一把。
have a good time玩得高兴
Did you have a good time in London?
你在伦敦过得愉快吗？
take a shower洗淋浴
We will have no water to take a shower.
来源：巧学英语
