I am a beginning user with Solidworks and currently taking a Solidworks fundamentals class.  I am putting an assembly together and everything is working great except for the sub-assembly; the sub-assembly has moving parts, as it should, but when I add it to the main assembly the parts no longer move. I'm not sure where to go from here.  I know I can add each piece separately but I would rather just add smaller assemblies to the larger ones.

Thanks for your help!