His mother inherited a farm worth 15,000 dollars a year.此句中worth为形容词,作后置定语.
不接不定式,接动名词,这是worth的固定用法,这是考点,需记忆.
worth做名词时,指价值、财富.例句：This picture is of great worth.
worth作为形容词,用法上类似于介词,后接名词、代词、数字或者动词的ing形式三个词都是形容词,都有“值得的”的意思,但用法或搭配关系不同.
1. worth是一个只能作表语的形容词,意思为“值……的”、“相当于……的价值的”、“有……价值的”、“值得……的”.后接名词、接动名词的主动形式.例如：
This second-hand car is worth $2000 at the most.
The exhibition is worth a visit/visiting.
It’s not worth getting angry with him.
The question is not worth discussing again and again.
2. worthy可作表语,也可作定语.作定语时意思为“有价值的”、“值得尊敬的”、“应受到赏识的”；用作表语时意思为“值得……的”、“应得到……的”,其后接of sth.,也可以后接to do sth.,例如：
①That is worthy of note. 那件事值得注意.
②This phenomenon is worthy of being studied. 这种现象值得研究.
③This problem is worthy to be considered. 这个问题值得考虑.
④The film is worthy to be seen again. 这部电影值得再看一遍.
⑤This is a worthy English-Chinese dictionary. 这是一本有价值的英汉词典.
⑥This is a worthy article. 这是一篇值得一看的文章.
⑦He said he was not worthy to accept such honour
⑧The school has educated many worthy young people.
⑨The question is not worthy to be discussed again and again.
作后置定语时,必须用“worthy of +名词”结构.例如：
⑩There is nothing worthy of mention. 没有值得一提的事情.
②This is behavior worthy of praise. 这是值得称赞的行为.
③ Something find and rare --- something worthy of the honor of being owned by Jim.
注：“worthy of+动名词”与“worth+动名词”在形式上完全不同：worthy of后面接被动式的动名词；而worth后面接主动式的动名词,虽然在形式上是主动的,但其意义仍然是被动的.试比较：
The second-hand house is worthy of being bought. = The second-hand house is worth buying.
3. worthwhile与worthy一样,既可作表语,又可作定语.表示某事因重要、有趣或受益大而值得花时间、金钱或努力去做,一般做“值得的”、“值得做的”、“有意义的”解.用作表语时,可接动名词或动词不定式.例如：
The Summer Palace is worthwhile going / to go to have a visit.
Helping old people is a worthwhile activity.
Thank you for your worthwhile suggestion.
I really feel I am doing something worthwhile and I am having a great time doing it
worth, worthy, worthwhile的用法区别【二】
worth, worthy, worthwhile都是形容词,意为"值得".
1. worth： be worth + n. 当名词为金钱时,表示"…… 值得……"
常见的有：
It ’s worth while to do.
It ’s worth（someone’s）while doing
be worth doing sth. "……某事值得被做"
The question is not worth discussing again and again. 这问题不值得反复讨论.
2. worthy：
be worthy of +n. 当名词为抽象名词时表示"……值得……"
be worthy to be done "某事值得被做"
The question is not worthy to be discussed again and again.
His deed is worthy to be praised.
3. worthwhile： be worthwhile to do sth "值得做某事"
It is worthwhile to ask him to join the club.值得邀请他加入俱乐部.
典型例题
It is not ____ to discuss the question again and again.
A. worth B. worthy C. worthwhile D. worth while
答案C. 由worth的用法可知,此句只适合词组be worthwhile to do sth..选C.
为何不选D,worthwhile 和worth while怎么区分等等问题,在此做一解释：
worthwhile可修饰名词或接不定式：
be worthwhile to do sth "值得做某事"
It is worthwhile to ask him to join the club.值得邀请他加入俱乐部.
worth不能单独放在名词前面作定语,当它与while构成worthwhile时则可作前置定语.这时,worthwhile = worthy.
例如：
①This is a worthwhile book. （该句可改为：This is a worthy book. = This book is worth reading. = This book is worthy of being read. = This book is worthy to be read. ）这本书值得一读.
②It is worthwhile effort. 这是值得努力做的事.
Worth while:
It作形式主语时,worth后面一般应加上while,后面接动名词或动词不定式.真正的主语为动名词或动词不定式.
接动名词或动词不定式的区别是：while前面有所有格或者后面接人时,一般接动词不定式；没有所有格时,一般接动名词.
It is worth while doing sth
It is worth one's while to do sth.
例如：
①It is worth our while to use waste materials. 废物值得利用.
②It is worth while pointing out that heating may bring about certain change in the structure of any material. 值得指出的是,加热会使任何物质的结构发生某种变化.