英语中，worth堪称怪异之词，其词性的归类历来在语法界里颇有争议，且用法也十分古怪。有人将其划归形容词（称为A派，如朗曼大辞典、英汉大辞典等），有人把它划归介词（称为P派，如牛津大辞典、新英汉辞典、英华大辞典、英汉大学辞典、远东大辞典等），互不兼容。
首先，worth具备以下语法特征：
1. 可有比较级与最高级形式。例如：
She is a woman more worth than any men.
Of all the designs, this is the most worth consideration.
2. 可为副词所修饰。例如：
The book is well worth reading.
It’s hardly worth troubling about.
Whose life, whose thoughts were little worth.
3. 可作补语（主补或宾补）。例如：
I paid only ￡300 for this used car but it is worth much more.
That’s the result —— I’ve found it worth reporting to the manager.
4. 可带宾语。例如：
The news is worth notice.
Don’t lock the door; it isn’t worth it.
A bird in the hand is worth two in the bush.
Take the story for what it is worth.
He says life wouldn’t be worth living without friendship.
以上，第1、2、3方面虽然符合形容词的基本语法特征，但却不符合介词的语法特征；而第4方面虽然符合介词的基本语法特征，却又不符合形容词的语法特征。于是又出现一种折衷的方案，即主张worth既可作形容词，又可作介词（称为X派，如新韦氏国际大辞典、英汉辞海、最新四用辞典等），彼此兼容。
平
心而论，A派与P派的观点各有所长，但又都难以自圆其说；而X派虽能兼蓄并拢，却又难免骑墙之嫌。的确，这是英语一个与身俱来而又万般无奈的语言结构问
题。说穿了，任何自然语言在形成与演变的过程中都不可避免地带有先天性或历史性的缺憾。毕竟，语言不是科学，无须保证精确；语言也不是艺术，何必苛求完
美？
依
笔者之见，可作如下分析。实际上，英语中存在着一类带“动能”的形容词，不妨称之为“动量形容词”（kinetic
adjective）。此类形容词在联系动词（link verb）的驱动下，其潜在的动能被激活了，于是便发挥替代动词的功能。换句话说，“联系动词 +
动量形容词”即可充当动词使用。诸如be afraid, be aware, be busy, be ready，be sorry, be
sure等等结构均可作此理解。试看下例：
I am afraid (= fear) I won’t be able to arrive in time.
We are aware (= realize) he is a deceiver.
He was busy (= was occupied) in cooking the dinner.
They were ready (= prepared) to go fishing.
I felt sorry (= regretted) that we hadn’t let him know the news earlier.
She is sure (= knows for sure) that she will succeed.
无疑，worth当属于此类“动量形容词”。如此一来，对它所表现出来的上述主要语法特征就都可以得到合理的解释。这一点，从某些语法著作中我们似乎亦可间接找到若干佐证。早在20世纪初，北欧英语语法权威O·Jesperson在其语法巨著A Modern English Grammar on Historical Principles中指出，worth其后的名词或动名词都作为它的宾语。上个世纪60年代，我国著名的英语辞典学家葛传椝在其所著的《英语惯用法词典》中也隐约表露了这种倾向，他说：“我们不妨把worth看
作transitive verb（及物动词）的present
participle（现在分词），把那后面的noun（名词）或gerund（动名词）看作它的object（宾语）。”我国另一个语法学家张道真亦持
类似观点。他在其著作《实用英语语法》中则进一步明确写道：“be + worth构成的谓语后可跟一宾语。”
worth的怪异之处还表现在它的用法上。
1. worth的比较级与最高级形式有别于一般的单音节形容词，不是worther、worthest，而是more worth、most worth。据考证，该形式最早出现于莎士比亚的剧作中，沿用至今。例如：
There is nothing more worth than what they have discovered.
Which of the three cities is the most worth visiting, Paris, London or New York?
2. worth不能为very所修饰，但可为very much或well及其比较级better、最高级（the）best所修饰。例如：
1）（误）He had something very worth saying..
2）（正）He had something very much worth saying.
3）（正）The novel is well worth reading.
4）（正）The film last night was better worth seeing than this one.
5）（正）The day is（the）best worth recalling.
3. worth属补语形容词，即在句中只作补语，一般不作定语（除非后置场合）。而且，作补语时，不可单独使用。例如：
6）（误）This is worth.
7）（正）This is worth five yuan.
8）（正）This is worth doing.
9）（正）It is worth this.
4. worth
不接不定式（短语），而接动名词（短语）作其宾语。其后接的宾语——动名词（短语），语法上必须采取主动形式，但逻辑上却表达被动意义。实际上，该动名词
（短语）与句子的主语在逻辑上构成动宾关系，即句子的主语应是该动名词（短语）的逻辑宾语。因此，该动名词（短语）只能来自及物性质的动词（短语），而不
可来自不及物性质的动词（短语）。试看下列几句：
10）（误）They are not worth to help.
11）（误）He isn’t worth waiting.
12）（误）I think the place is worth going.
13）（误）I don’t think you are worth publishing your poems.
14）（误）The event is worth being looked forward to.
15) （误）It is worth discussing the question again.
以上均为误句。因为，句10）里，worth之后用上不定式to help作宾语；句11）、句12）里的waiting
与going均来自不及物动词；句13）里的you无法作publishing的逻辑宾语；句14）里的being looked forward
to 用的是被动形式；句15) 里的it属形式主语，而句子的真正主语是动名词短语discussing the question，这么一来，worth便成了无“宾语”的单独形式了。可作如下修改：
15）（正）They are not worth helping.
16）（正）He isn’t worth waiting for.
17）（正）I think the place is worth going to see.
18) （正）I don’t think your poems are worth publishing.
19) （正）The event is worth looking forward to.
20）（正）The question is worth discussing again.
值得留意的是，worth有3种异体形式，即worth while、worth-while和worthwhile，但其用法与worth却又略有不同：
1. worth while属通用形容词，既可作补语，又可作定语。而且，作补语时，可单独使用。试看：
Do you think it’s worth while quarrelling with me?
The information was not worth-while.
Your brother is a worthwhile fellow.
2. worth while等异体形式既可接动名词（短语），又可接不定式（短语）作其宾语。而且，与worth不同的是，该动名词（短语）或不定式（短语）同句子的主语并不构成逻辑上的动宾关系。因此，它们既可来自及物性质的动词（短语）（但须自带宾语），也可来自不及物性质的动词（短语）。例如：
It’s not worth while losing your temper like that.
It’s scarcely worth while looking for her around here.
I’d think it (is) well worth while to have a good rest.
分析下列句子：
21）（误）Her advice is worth while taking.
22）（误）Her advice is worth while to take.
23）（误）It is worth taking her advice.
24）（误）You are worth to take her advice.
句21）、句22）用的是worth while，其间的taking与to take均来自及物动词，但却缺少自带的宾语；句23）用的是worth，由于句子的主语it本身必须兼作taking的逻辑宾语，因此与自带的宾语her advice构成冲突；句24）用的也是worth，但其后接的宾语为不定式短语to take her advice，不合乎语法要求。可作如下修改：
25）（正）Her advice is worth taking.
26）（正）It is worth while taking her advice.
27）（正）It is worth while to take her advice.
28）（正）You are worth while to take her advice. (或：It is worth while for you to take her advice.)
再看以下两个句子：
29）（正）It is worth remembering that a friend in need is a friend indeed.
30）（正）It is worth while remembering that a a friend in need is a friend indeed..
上述两个句子都正确。因为，两句中的it均为形式主语，但在句29）中，其后移的真正主语是that从句；而在句30）中，其后移的真正主语却是整个动名词短语, 即“remembering + that从句”。
3. worth while等异体形式，还可在worth与while之间插入一个名词属格或物主代词。例如：
The work is not pleasant, but I promise you I’ll make it worth your while.
If you do this job for me I’ll make it worth your while.
Perhaps it wouldn’t be worth our while to come here.
It’s not worth students’ while reading this article, because it isn’t easy for them to understand.值得提醒的是，worth还有另外一个派生词worthy，其意义和worth非常接近，且其用法也同worth一样，十分怪异。两者在使用时极易混淆，这无疑又为之“雪”上加“霜”，增“玄”添“难”了不少。