''one''这个词在中学英语课本中使用的频率很高，其用法归纳起来有下列几种。

一、作数词用。

1. 具有形容词性，有“一”之意。如：

one half一半；one or two days一两天

I only have one thing to stay.

此时one比a语气强些。

2. 具有名词性，有“一；一个；一个人”等意。如：

How many sisters do you have? I have one.

One of the boys is not here.

此外，one用在名词后，“第一”的意思。如：

No. one , Page One, Picture One

二、作形容词用。

1. 与表示时间的名词连用，构成副词性词组，作“某一”，“有一”等解时，其前不加介词。如：

one morning(night)有个上午(晚上)，one Friday有一个星期五

注意，one day既可指过去“有一天”，也可指将来“有朝一日”。细读下面两句子：

One day a young man came to see me.

One day we'll go to the moon by spaceship.

注意区别下面两个句子，前一句用one，前面不加介词；后一句用a，前面加了介词。

One summer afternoon I met him in the street.

One a summer a afternoon I met him in the street.

2. 有"the same''之意，即“同一的”“一致的”。如：

in one voice异口同声地 ; one price一样价钱

It is all one to me. 这对我是一样的。

3.有“（作对比）一方的”意思。如：

from one side to the other从一头到另一头

To say is one thing and to do is another 说是一回事，做又是另一回事。

三、作代词用。

1. 作不定代词，有“任何人”，“谁都”的意思。如：

One must love one's (his) country谁都必须爱国。

One for all and all for one.个人为集体，集体为个人。

2. 代表人称代词，“个人”，“某人”之意。如：

run as fast as one can尽量跑得快马

do one's best 竭尽所能，尽力

3. 作“一个”，“一本”，“一件”等解，用来代替上文提到过的某个可数名词，以避免重复，其前不加任何限定词。如：

My pen is broken. I must buy one.

''Have an apple, please."

"No, thanks. I've just had one."

注意：one与it都可替代上文出现的某个名词，但用法不同。one用来指代上文出现的某类物中的一个，it指代上文中出现的那个物。细读下文，仔细比较：

1) A: Do you have a knife?

B:Yes, I have one.

A: Give it to me ,please. B: OK. Here it is.

2) A: Do you have any pencils?

B: Yes, I have one.（此时复数形式用some）(Yes, I have some.)

3) A: Would you like the watch? B: Yes, I'd like it.

4. one与形容词连用时，其前常有a, the, this, that, next,last, my, her等限定词。如：

a small one, the blue one, my new one, his big one, your old one（one前有形容词修饰时，才可以与形容词性物主代词或名词所有格连用。如：Jim's new one)

5. one可以与疑问代词(which)、相互代词及序数词连用。如：

1) Which one is yours?

2) This one is too heavy. Give me another one.

3) The second one is bigger.

6. one的复数形式为ones。但要注意：ones只有在其前修饰语时才能用。如：

Which ones are theirs? The blue ones are theirs.

I want big ones, I don't want small ones.

7. 作对比用时，one为“一个、一方”之意。如：

1) There are two(three) balls. one is yellow. The other is (The others are) black.

2) This is my sock. The other one is under the desk.

8. these ones与those ones很不普通。如最好不说：These ones are not good. I want those ones.要说：These are not good. I want those.

one的用法