疑问：either 和 neither 均为中位限定词，two, three 等为后位限定词，为什么不可说 either two boys, neither two girls 呢？

【答】你这个问题，跟限定词的位置没有关系。

either 和neither 作限定词时，已经表示“两者之一”和“两者任何一个都不”。所以不可以跟two 同时出现，不可以同时作限定词。

Did you see either boy?

你看见两个男孩中的任何一个吗?

Neither side is willing to make a move.

双方都不愿采取行动。

either 和neither 只有用作代词时，of 后面短语才可以出现two，即便不加two，也表示“两个”，例如：

Neither of my two friends has come yet.

Neither of my friends has come yet.

我的两个朋友都还没来。

1 either和neither作为中位限定词只能表示二者中的任一个，这就决定了其不能用于复数名词前，自然也就不能和数词连用了。这就和中位限定词each和every也不能后接复数名词是一个道理。either和neither除了是限定词外，还是不定代词，用作名词词组的中心词。此时可以通过介词of引出表示二者总体的名词，该名词可以用数词two修饰，也可不用，因为总体一定是二个。但此时是不定代词的用法，已经超出了限定词的范畴。

2 both和all一样，都是前位限定词，而不是后位限定词。前位限定词必须位于中位和前位限定词之前。没有例外！

网友应该记住哪些限定词是前位，哪些是中位，哪些是后位。花上十几分钟时间分析一下各自有什么特点，分析加记忆。我在二十年前记过一次，至今不忘，因为是分析基础上的记忆。

另外，应该记住一条，语法分析和理解应用离不开逻辑，时刻将语法分析和逻辑分析结合应用，凡是违犯逻辑的分析一定是错误的分析。

补充

刘清沅老师的补充非常有用。希望网友收藏记忆。

【一】限定词概述
定词是与名词密切相关的词类，包括冠词（a（n），the）、形容词性指示代词（this，that， these，those）、形容词性物主代词（my，your，our，etc．）、形容词性不定代词（both，every，much，some， etc．）、数词（one，two，etc；first，second，etc．；one-third，three-fifths，etc．）和特指形容词（next，only，etc．）。限定词用于名词的前面，限定名词所指的范围，表示该名词是特指还是泛指，是定量还是不定量。限定词的使用并非随意，受着名词种类及形式的制约，与名词有着特定的搭配关系，在多个限定词连用时相互之间还有着相对固定的位置

【二】限定词与名词的搭配关系
限定词一般不用于专有名词，用于普通名词时要根据名词的数和类别来决定。
普通名词可分为如下三类：
单数可数名词，如：a desk, a pencil等。
复数可数名词，如：desks, pencils等。
不可数名词，如：coffee, fire等。
各限定词与三类名词搭配关系可分为以下几种情况：
A. 能与三类名词搭配的限定词
定冠词the, 如：the book, the books, the bread等。
物主代词、名词所有格，如：
my / John's book
my / John's books
my / John's bread
all / some / any / no，如：
all / some / any / no book
all / some / any / no books
all / some / any / no bread
other / such，如：
other / such student
other / such students
wh -words (eg. what, which, whose等）。
I'm sorry you had such terrible weather.
Which John do you mean, John the baker or John the post man？
Note:
such经常与不定冠词连用构成such + a(n) + adj + 名词结构。如：
I've never lived in such a large house as this before.
They haven't had such a good time for ages.
B. 只能与单数可数名词搭配的限定词

如：a (n), each, every, either, one等。
I told every student to come.
She knows every pupil of the class.
You may use either hoe.
C. 只能与复数可数名词搭配的限定词
如：both, (a) few, several, these / those, a (great) number of, two / three, many等。
We're asking a few friends round to dinner.
A great number of animals are killed every year.
Note:
many后面可以跟a (n)放在单数可数名词前，尽管还表示“许多”的意思，但动词用单数。
Many a man is going to welcome the foreign guests.
Many a friend has been invited to this party.
D. 只能与不可数名词搭配的限定词
如：(a) little, a bit of, a great amount of, a great deal of, much 等。
In fact I know a bit of Spanish.
A large amount of money is spent on tobacco every year.
E. 能与单数可数名词和复数可数名词搭配的限定词
如：the first / second, the next, the other 等。
What's the next thing to do?
John wanted to know what the other doctors suggest.
F. 能与复数可数名词和不可数名词搭配的限定词
如：a lot of, plenty of, lots of, enough, more, most等。
There is enough food for everybody.
There aren't enough tools to go around.
G. 能与单数可数名词和不可数名词搭配的限定词
如：(the) least, this, that等。
He hadn't the least thought of his own interests.
She fainted at the least sight of blood.
【三】限定词与限定词的搭配关系

在名词词组中，当两个以上的限定词同时出现时，限定词之间就存在前后顺序问题，根据限定词不同的搭配位置，限定词可分为中位限定词、前位限定词和后位限定词。

前位限定词（Predeterminers)：all, both, half, double, twice; one third, two thirds等。

中位限定词（Central determiners ）包括：冠词；指示词（this / that / these / those) ;形容词性物主代词，名词所有格（my, John's)；量词(some, any, no, every, each, either, neither, enough, much等）；wh-words (what, which, whose等）。

后位限定词（Postdeterminers）：基数词；序数词; last, next, other, another等; such; many, little, few, several, more, less等。

The teacher asked his students to write their answers on every other line.
老师要求学生隔一行写出答案。
Both my brothers have graduated from universities.
我两个兄弟都大学毕业了。
The old men had a very good time during all these last few days.
这些老人在最后一段日子里过得很愉快。

在限定词的搭配中，一般的顺序都是前位-中位-后位，中位限定词之间和前位限定词之间是互相排斥的，即：两个中位限定词或两个前位限定词不能同时修饰中心词-名词，而后位限定词则可以并列修饰中心词。
Mr Harrison showed us a few more samples.
Tom broke his leg on New Year's day. It took him the next few weeks to get over it.
汤姆新年那天摔断了腿，几个星期后才恢复。
The girl's parents invited several hundred guests to her birthday party.
女孩的父母邀请了几百名客人参加她的生日晚会。

Note:
限定词使用规则：
限定词的分类比较复杂、难记。一般情况下，可以运用以下几条简单、实用的规则。
A.把all和both放在其他限定词之前。如：
The little boy ate all the food.
All such problems should be considered.
Both my hands were seriously hurt.
B.把many / much, more / most, few / little放在其他限定词之后。如：
His many successes made him famous.
John's few friends speak highly of him.
With the surrender of the enemy troops, no more fighting was expected there.
C.感叹句中，把what和such放在a(n)之前。如：
What a lovely girl!
I've never seen such a crowd!
四、几组限定词的用法比较
（一）some, any, no的用法
some, any, no同是能与单数可数名词、复数可数名词和不可数名词搭配的限定词。
1.some和any表示“一些，若干几分”等含义，一般情况下，some用于肯定句,any用于疑问、否定、条件句中。
Have you got any aspirins?
Mr White has some flowers in his garden.
We haven't invited any students to the party.
If you want any glasses, I'll send you some.
2.any 还可以用于实际上含否定意思的肯定句中。例如，含有never, without, hardly等词的肯定句。
The young accountant seldom makes any error in his books.
I can answer your questions without any hesitations.
The noise of the party prevented me from getting any sleep.
3.some可以与others连用。
Some people like the sea, others prefer the mountains.
Some students answered Yes and others answered No.
4.如果说话人预期肯定回答时，some也可用于疑问句。
Don't you give him some tickets?
"I've just been shopping." "Oh, did you buy some rice?”
some还可用在表示劝请、请求、命令的疑问句中。
Won't you have some more beer?
Could you buy me some clips?
5.any用于肯定句中，表示“任何，无论哪一个”。
Any child would know that.
6.No的含义相当于not any (a)。
No cigarette is completely harmless.
There were no letters for you this morning.
no和any相似，它不能与另一个限定词连用。与the, my, this, that等相遇时用none of代替。
None of my friends live near my house.
I like none of that music.
no可以和一个带-ing的动词连用，表示不允许干某事，这时不能用not any代替。
No Smoking!不准吸烟！
No Parking!禁止停放车辆！
No Waiting!禁止（车辆等）在此等候！
7.有时no的意义不止是not (a)或not any，而是not at all（完全不是，决不是）。
He is no fool.
(= He is not a fool.）
It is no easy task.
(= It is not an easy task.）
（二）all, both, every, each, either, neither的用法
1.all, both同属前位限定词，但all可以与三类名词搭配，both只能与复数可数名词搭配，从意义上讲both指两者，all指三者或三者以上。如：
How much time will you take for all this work?
All children can be naughty sometimes.
I got both these vases in Spain.
Both cats are asleep.
all和both用于否定时表示部分否定。
例如：
I cannot promote both of you.
我不能使你们两个都提升。

All flowers in his garden are not red.
他花园里的花并非都是红色的。
Both (of them) are not my brothers.
他们两个之中，只有一个是我的兄弟。
另外，表示部分否定的词还有every (everyone)。
例如：
Every man can not be a poet.
并非人人都可以成为诗人。
要表达全部否定要用none / no (nobody) , neither, either等。
例如：
I cannot promote either of you.
你们两个我都不能提拔。
No flower in his garden is red.
他花园的花都不是红的。
2.all 和every从意义上十分相近，都用来泛指人或物，然而两者各自与名词搭配的类别不同，every只能与单数可数名词连用。如：
All Mondays are horrible.
(= Every Monday is horrible. )
all后可以跟the或this, my等限定词，而every却不行。
例如：
All the boys of this class are able to run faster than their teacher.
试比较：
She was here all day.她在这里呆了一整天。
She was here every day. 她天天都在这里。
3.every和each同属中位限定词，都可与单数名词连用，且意义相近，表示‘每个’，然而every和each并不完全一样，every强调整体概括，each则表示个别概念。

Each day is better than the one before.

一天比一天好。
Every player was in good form.
每个运动员都处于最佳状态。
如果不特别强调某一意义时，every和each可以互换。
例如：

We want every child to succeed.
我们希望每个孩子都成功。
Each child will find his own personal road to success.
每个孩子将会找到他个人的成功之路。
each可以指两个或两个以上的人或东西，every却不能指两个，只能指三个以上的数量。
Each * has its own physical and psychological characteristics.
男女各有其身体上和心理上的特点。（不能说every *...)
另外，如有其他限定词同时修饰中心词，each可作代词取each of的形式，而every则只能作限定词。
Each of my parents gave me presents for Christmas.
过圣诞节时我父母每人都给我送了礼物。
4.either 和neither 同属中位限定词，与名词连用时不能和其他限定词同用（如冠词，物主代词，或指示代词）。either 和neither都只修饰单数可数名词，动词也用单数。例如：
Either day is OK.
两天中哪一天都行。
Neither car is exactly what I want.
这两辆车都不是我想要的。
There were trees and flowers on either side of the street.
街两旁都有树和花。
Either kind of school is quite suitable.
两种学校都挺适合。
either也可指‘两个都’与both的意义相近，但both后接复数名词,either则只接单数名词，而且both还可与其他限定词搭配。
Both (of) my children have been to America.
另外，当either, neither与其他限定词连用时，则使用either of, neither of结构。例如：
Either of the girls is quite capable of the work.
两位女孩都能胜任这项工作。
Neither of his cats has been fed.
他的两只猫都还没喂。
注意：此时动词用单数，不能用复数。但在否定句中却常用复数，neither of后单复数动词都可以，只是复数常用在非正式文体中。 
I don't think either of the girls are capable of the work.
我认为这两个女孩都不能胜任这项工作。
Neither of your two answers is correct.
你的两个回答都不正确。

同意曹老师的看法，就是说通常而言不满足语法（在这里也就是指前位限定词+中位限定词+后位限定词的语序）是不行的，但是只满足语法不满足词义、逻辑也行不通。