这类复合名词变复数有三种情况:
1.前面不变,后面变.如 an apple tree变为some apple trees.大部分都属此类.boy students也属于这一类的.
2.前后都变,这样的只有man,woman在前面的时候.如 a man teacher变为some men teachers.a woman doctor变为 two women doctors.
3.sports在前只用复数形式.如:have a sports meeting 和 have some sports meeting.