which gene to choose as a realtime PCR control gene at different stages?

I want to check the mRNA level of certain gene at different stages, for a real-time PCR assay, which gene should I select as the control gene?
Thanks for your attention and kindly reply!
Goffee from Shanghai

you could try two or three genes as reference genes ,
I usually try ama-1 first ,
then act-1 , gpd-1/gpd-2(a GAPDH homolog ),sc-35,etc.
Good luck .