1.worth 只作表语,不能作定语修饰名词
It is worth doing sth 或者跟名词,价格,用主动
the book is worth reading.
the book is worth the price.
2.worthy 可作表语也可作定语
It is worthy of being done 或
It is worthy to be done 用被动
如果加名词,加of The book is worthy of the price.
3.worthwhile 可作表语和定语
It is worthwhile to do或
It is worthwhile doing