首先，worth具備以下語法特征：
1. 可有比較級與最高級形式。例如：
She is a woman more worth than any men.
Of all the designs, this is the most worth consideration.
2. 可為副詞所修飾。例如：
The book is well worth reading.
It’s hardly worth troubling about.
Whose life, whose thoughts were little worth.
3. 可作補語（主補或賓補）。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. 可帶賓語。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方面雖然符合形容詞的基本語法特征，但卻不符合介詞的語法特征；而第4方面雖然符合介詞的基本語法特征，卻又不符合形容詞的語法特征。於是又出現壹種折衷的方案，即主張worth既可作形容詞，又可作介詞（稱為X派，如新韋氏國際大辭典、英漢辭海、最新四用辭典等），彼此兼容。
平
心而論，A派與P派的觀點各有所長，但又都難以自圓其說；而X派雖能兼蓄並攏，卻又難免騎墻之嫌。的確，這是英語壹個與身俱來而又萬般無奈的語言結構問
題。說穿了，任何自然語言在形成與演變的過程中都不可避免地帶有先天性或歷史性的缺憾。畢竟，語言不是科學，無須保證精確；語言也不是藝術，何必苛求完
美？
依
筆者之見，可作如下分析。實際上，英語中存在著壹類帶“動能”的形容詞，不妨稱之為“動量形容詞”（kinetic
adjective）。此類形容詞在聯系動詞（link verb）的驅動下，其潛在的動能被激活了，於是便發揮替代動詞的功能。換句話說，“聯系動詞 +
動量形容詞”即可充當動詞使用。諸如be afraid, be aware, be busy, be ready，be sorry, be
sure等等結構均可作此理解。試看下例：
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.
無疑，worth當屬於此類“動量形容詞”。如此壹來，對它所表現出來的上述主要語法特征就都可以得到合理的解釋。這壹點，從某些語法著作中我們似乎亦可間接找到若幹佐證。早在20世紀初，北歐英語語法權威O·Jesperson在其語法巨著A Modern English Grammar on Historical Principles中指出，worth其後的名詞或動名詞都作為它的賓語。上個世紀60年代，我國著名的英語辭典學家葛傳椝在其所著的《英語慣用法詞典》中也隱約表露了這種傾向，他說：“我們不妨把worth看
作transitive verb（及物動詞）的present
participle（現在分詞），把那後面的noun（名詞）或gerund（動名詞）看作它的object（賓語）。”我國另壹個語法學家張道真亦持
類似觀點。他在其著作《實用英語語法》中則進壹步明確寫道：“be + worth構成的謂語後可跟壹賓語。”
worth的怪異之處還表現在它的用法上。
1. worth的比較級與最高級形式有別於壹般的單音節形容詞，不是worther、worthest，而是more worth、most worth。據考證，該形式最早出現於莎士比亞的劇作中，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不能為very所修飾，但可為very much或well及其比較級better、最高級（the）best所修飾。例如：
1）（誤）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屬補語形容詞，即在句中只作補語，壹般不作定語（除非後置場合）。而且，作補語時，不可單獨使用。例如：
6）（誤）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（短語），而接動名詞（短語）作其賓語。其後接的賓語——動名詞（短語），語法上必須采取主動形式，但邏輯上卻表達被動意義。實際上，該動名詞
（短語）與句子的主語在邏輯上構成動賓關系，即句子的主語應是該動名詞（短語）的邏輯賓語。因此，該動名詞（短語）只能來自及物性質的動詞（短語），而不
可來自不及物性質的動詞（短語）。試看下列幾句：
10）（誤）They are not worth to help.
11）（誤）He isn’t worth waiting.
12）（誤）I think the place is worth going.
13）（誤）I don’t think you are worth publishing your poems.
14）（誤）The event is worth being looked forward to.
15) （誤）It is worth discussing the question again.
以上均為誤句。因為，句10）裏，worth之後用上不定式to help作賓語；句11）、句12）裏的waiting
與going均來自不及物動詞；句13）裏的you無法作publishing的邏輯賓語；句14）裏的being looked forward
to 用的是被動形式；句15) 裏的it屬形式主語，而句子的真正主語是動名詞短語discussing the question，這麽壹來，worth便成了無“賓語”的單獨形式了。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種異體形式，即worth while、worth-while和worthwhile，但其用法與worth卻又略有不同：
1. worth while屬通用形容詞，既可作補語，又可作定語。而且，作補語時，可單獨使用。試看：
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等異體形式既可接動名詞（短語），又可接不定式（短語）作其賓語。而且，與worth不同的是，該動名詞（短語）或不定式（短語）同句子的主語並不構成邏輯上的動賓關系。因此，它們既可來自及物性質的動詞（短語）（但須自帶賓語），也可來自不及物性質的動詞（短語）。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）（誤）Her advice is worth while taking.
22）（誤）Her advice is worth while to take.
23）（誤）It is worth taking her advice.
24）（誤）You are worth to take her advice.
句21）、句22）用的是worth while，其間的taking與to take均來自及物動詞，但卻缺少自帶的賓語；句23）用的是worth，由於句子的主語it本身必須兼作taking的邏輯賓語，因此與自帶的賓語her advice構成沖突；句24）用的也是worth，但其後接的賓語為不定式短語to take her advice，不合乎語法要求。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.)
再看以下兩個句子：
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..
上述兩個句子都正確。因為，兩句中的it均為形式主語，但在句29）中，其後移的真正主語是that從句；而在句30）中，其後移的真正主語卻是整個動名詞短語, 即“remembering + that從句”。
3. worth while等異體形式，還可在worth與while之間插入壹個名詞屬格或物主代詞。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還有另外壹個派生詞worthy，其意義和worth非常接近，且其用法也同worth壹樣，十分怪異。兩者在使用時極易混淆，這無疑又為之“雪”上加“霜”，增“玄”添“難”了不少。