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
worth 在句中 与 表示时间的短语 连用，在柯林斯词典里作如下解释：
【COMB in QUANT Worth combines with time expressions, so you can use worthwhen you are saying how long an amount of something will last. 可维持 (一段时间) 的东西】
例：
a week's worth of food 可够你吃一周的食物
You've got three years' worth of research money to do what you want with.
你有 可维持3年的研究经费 来做你想做的事情。
所以，问题中的句子last time I had two weeks' worth of weightlifting in three days and I hurt myself.应该是如下含义：【上次，我在三天内完成了两周才能做完的举重练习（超负荷锻炼），所以我把自己搞受伤了。】