In Mandarin, if we have two VO in order the second one indicates the purpose of the first action, something like "in order to" or just "to" in English, as in:
我回家学习中文 - I'll go back home (in order) TO study Chinese.
But I've seen many times a 来 appearing to convey that role, as in:
有些作业老师让学生拿回家来做 - There are some homeworks the teacher let the students take back home TO do.
So, my question is: Can I always use 来 when I want to convey that meaning or does it have some specific cases?