worth用法如下：
worth,worthy,worth-while都為adj. 意為"值得".
1. worth： be worth + n. 當名詞為金錢時,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. 當名詞為抽象名詞時表示"……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.