free time activities为什么不是free time's activities?

问题描述:

free time activities为什么不是free time's activities?

这里名词短语free time作了activities的定语.类似的还有part time job.不过一般情况下充当定语的名词短语都是用连字符"-"连接起来的.如:a face-to-face conversation面对面的谈话,a two-day trip两天的旅行.