名词修饰名词。名词做定语。这样的名词词组变复数指在后面被修饰词变成复数而前面的修饰词不变，但想man,weman 做修饰词时，修饰词被修饰词都变复数。例如：boy student----boy students, girl student-----girl students. man doctor----men doctors,womon nurse---women nurses.
所以男学生用英语“boys students”不对。
Each boy-student and each girl-student in this class is extremely fond of reciting poetry.
这个班的每个男生、每个女生都特别善于背诗。
www.hotdic.com
In Fran Brown's first-grade class last month, a brown-haired boy spat on a fellow student.
上个月在弗兰·布朗所教的一年级的班上，一个棕色头发的男孩向一个同学吐痰。
article.yeeyan.org
This is the first experiment that we did -- eight year-old boy on your right teaching his student, asix year-old girl, and he was teaching her how to browse.