offspring will be born to return them one day to their natural environment.请问them one day的意思?

问题描述:

offspring will be born to return them one day to their natural environment.请问them one day的意思?
完整句子:
There is always the chance that enough offspring will be born to return them one day to their natural environment.

总是有机会来繁衍足够的后代子孙,并在将来的某一天把他们归还到原来所属的自然环境中.
ps:return 还有“归还”的意思