worth 相关用法?

金额所有格+worth+of+某物:价值多少的某物
20 dollars's worth of good:价值20美圆的货物。
worth doing sth.:值得做某事
sth. is worth doing. 某事值得做。

worth,worthy,worth-while都为adj. 意为"值得".
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.
典型例题
It is not ____ to discuss the question again and again.
A.worth B.worthy C.worth-while D.worth while
答案C. 由worth的用法可知,此句只适合词组be worth-while to do sth..因此选C.