It is _____ reading this book carefully.

It is _____ reading this book carefully.
A.worth B.well worth C.worthy D.worthwhile
分析解释一下四个选项各怎么用

worthwhile:[ 'wə:ð'(h)wail ]
a.值得(做)的
词形变化:
名词:worthwhileness
例句与用法:
1.That's worthwhile.
那是值得的.
2.Thank you for making my visit so worthwhile.I shall treasure your friendship and kind hospitality you have given me.
感谢你们使我的访问如此有价值.我将珍惜我们之间的友谊及你们给予我的盛情款待.
worthy:[ 'wə:ði ]
a.有价值的,可尊敬的,值得的,配得上的
词形变化:
副词:worthily 形容词比较级:worthier 最高级:worthiest 名词:worthiness 名词复数:worthies
例句与用法:
1.She proved herself a worthy successor to the former champion.
她证明了自己是前冠军的当之无愧的接替人.
2.We esteem him to be worthy of trust.
我们认为他值得信任.
3.He who does his duty is worthy of praising.
凡是忠于职守的人都值得奖励.
4.This book is worthy of reading.
这本书值得一读.
5.How was it possible to walk for an hour through the woods and see nothing worthy of note?
在树林中走了一个小时而没有见到什么值得注意的东西,这怎么可能
well worth:
很上算的
例句与用法:
1.The scheme is well worth a try.
这个计画倒值得一试.
2.The book is rather highly priced for the average pocket,but so well worth reading that it should be begged,borrowed or stolen rather than missed.
该书的定价很高,一般人是不敢问津的,但很值得一读.因此,得千方百计弄一本来看看,决不可错过.
worth:[ wə:θ ]
n.价值
prep.&a.值...钱,值得...的
词形变化:
动词过去式:worthed 过去分词:worthed 现在分词:worthing 第三人称单数:worths
例句与用法:
1.The house is worth a lot of money.
这栋房子值很多钱.
2.Whatever is worth doing at all is worth doing well.
任何值得做的事就值得做好.
3.The thief ran off down the road,so I chased him for all I was worth.
那个贼顺着马路逃跑,我就拼命紧追不舍.