1.worth：be worth + n.当名词为金钱时,表示"…… 值得……"
be worth doing sth."……某事值得被做"
The question is not worth discussing again and again.
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 againand again.
3.worth-while：be worth-while to do sth "值得做某事"
worth while：It is worth while doing sth
It is worth while sb to do sth.很值得，注意是“很”well worth doing：非常值得被（固定表达，不用very）