首先是冠词 a an 和the的用法
一、不定冠词a, an的用法
1.不定冠词a用在以辅音开头的名词前,an用于以愿意字母开头的名词前
A．用在单数可数名词前表示一类人或事物
A student should be polite.
A school is a place where student study.
B．首次提到某物
Once upon a time, there was a beautiful princess.
C．a有every之意
We have three meals a (every) day.
D．a有one之意,但不如one强烈
I have got a (one) car outside the building.
E．用于某些固定词组中
a little, a few, a lot of, in a hurry, have a rest, have a cold, make a living
2.不定冠词的特殊用法
A．用于序数词前,不表示顺序,而用来表示“又一,再一”之意.
I want to try a third time.
B．与most以及形容词原形连用,修饰名词,这是most表示“非常”的意思.
This is a most interesting book.
C．用在一些专有名词前或人名前,表示“像……那样的人”,“某个……”.
A Mr. White rang you this morning.
I’m going to buy an Olympus.
D．用在quite, rather, half, such等词后,用在how/ so + 形容词后
It’s so cold a day.
二、定冠词the的用法
1.表特指,或表示特定的或上文已提到的人或事物.
Can you see the woman in red?
He saw a man standing at the door. And the man was looking at him, too
2.用在单数可数名词前表示特定的一类.
The snake is a dangerous animal.
3.用在世界上独一无二的事物前.
the moon, the sun
4.用在演奏的乐器前.
I like playing the guitar.
5.用在序数词前.
The first month of a year is January.
6.用在表示方位的名词前.
Hainan is in the south of China.
7.用在形容词副词的最高级前.
He is the tallest in his class.
8.用在姓氏的复数前表示夫妇二人或一家人.
Sandy and Sue has already met the Blakes.
9.用在某些形容词前,表示一类人.
the poor, the rich, the old
We should take good care of the old.
10.用在“the+比较级,the+比较级”中表示“越……越……”
The more, the better.
11.在“动词+某人+介词+定冠词+人体某一部分”这 以结构中,习惯上用the,而不用物主代词.
The ball hit him on the head.
12.用于江河、海洋、山脉、群岛、沙漠等专有名词前.
The Yellow River, the Pacific Ocean, the Himalayas
13.用于含有普遍名词的专有名词前.
the Summer Palace, the Great Hall of the People, the Great Wall
14.用于一些固定的短语中
in the afternoon, in the end, all the time, at the age of, by the way, on the way home
三、不用冠词的情况
1.在表示人名、地名、国家名的专有名词前不用冠词.
2.在一类人或事物的复数名词前不用冠词.
I like ice-creams.
3.在不可数名词前不用冠词.
Water is important to us.
4.在节日、假日、星期几、月份、季节、日期前不用冠词.
March 8 is Women’s Day
It’s Monday today.
in January/ spring
5.在球类运动、一日三餐、棋类前不用冠词
What do you eat for breakfast?
play chess
play football/ basketball/ baseball/ badminton/ volleyball/ golf
have breakfast/ lunch/ supper
6.学科、语言、称呼语的名词前不加冠词.
We have Chinese, maths, English and some other subjects.
7.与by连用的交通工具前,表示乘坐某种交通工具时,不加冠词.
by bus/ car/ air/ plane/ boat/ bike/ ship/ sea 另：on foot
8.名词前有this/that等修饰时,不加冠词.
I don’t like this sweater, please show me another.
9.两个名词表示相对关系时,不用冠词.
father and son, husband and wife
They are doctor and patient.
下面是a an one的区别
1. 两者均可表示“一”的意思,有时可互换.如：About a [one] thousand students attended the meeting. 大约有 1 000 学生参加了会议.(在数字开头时,两者均可用；但若不是数字开头,则应用(one,如不可说 three thousand a hundred,而说 three thousand one hundred)A [One] Mr Smith wants to see you. 一个名叫史密斯先生的人想见你.(a Mr... 与 one Mr... 同义,也可说 a certain Mr...,但如果没有 Mr 这样的词,两者则不宜随便互换,否则含意会发生变化.比较： Mr One John Smith telephoned. 一个名叫约翰·史密斯的人打过电话来.I wish to become a Newton. 我想成为一个像牛顿那样的人.)All the prisoners escaped at a [one] stroke. 所有的犯人一下子都逃跑了.(at a stroke 和 at one stroke 均是习语,意为“一下子”、“一举”等.类似地有：at a [one] blow 一下子,一举；at a [one] bound 一跃,一跳；in a [one] word = 一句话,总而言之；be of one [a] mind = 意见一致；not for a [one] moment意见一致；绝不,完全不,从不)2. 尽管两者均可表示“一”,有时也可换用,但毕竟由于两者的词性不同,用法不同,在多数情况下是不能互换的：(1) 从词性上看：a (an) 是不定冠词,主要表示类别,即着重表示其后的名词是某物,而不是其他物；而a (an) one 表示“一(个)”时是数词,主要表示数量,即强调在数量上是一个,而不是两个或多个.比较：Give me a dictionary. 给我一本字典.(此处强调的是：我要的是一本字典,而不是一本教材,也不是一本小说等)Give me one dictionary. 给我一本字典.(此处强调的是：我要的是一本字典,而不是两本字典或多本字典)再比较以下一组表达在意义上的区别：more than a year 一年多 (如一年零三个月等)more than one year 不止一年 (如两年或三年等)(2) 由于 one 是数词,着重数量意义,所以当要强调数量、进行数量对比或回答 how many 的提问时,均应用 one,而不能用 a (an).如：He has only one pen, but I have two. 他只有一枝钢笔,但我有两枝.He has only one pen, but I have I want one box, not five. 我想要一个盒子,不是要五个.How many friends do you have here? — Only one. 你在这儿有多少个朋友?—— 只有一个.(3) 在某些表达中,两者均可用,但含义不同：at a time 每次,同时 at one time 一度,曾经as a man 就一个人的性格而论 as one man 一起,同时,全体一致地在某些表达中,两者均可用,虽含义相同,但表达不同：on a hot summer afternoon 一个炎热的夏日的下午on a hot summer afternoon (注意用介词 on)one hot summer afternoon 一个炎热的夏日的下午 (注意不用介词 on)an hour and a half 一个半小时 (通常不说 one hour and a half)one and a half hours a minute or two 一两分钟 (通常不说 one minute or two)one or two minutes 一两分种在绝大多数习语中,两者是不能换用的.如：in a hurry 匆忙in a hurry once upon a time 从前as a result 结果 all of a sudden 突然one day 一天 one by one 一个一个地one and all 全部,每个人 one and the same 完全相同的
