(SG2)Question on Firing Twice

Hi Everyone,

I know this question has been asked before and will probably be asked
again, 
but what is the rulling behind firing more than once per turn?	I know
the 
rules state a model cannot fire more than once per turn, but what
happens if 
you transfer actions using the "Give Orders" action to a squad that has 
already activated?  Can they take a second fire action that turn?

My group has always played that you can, but before I run my demo I'd
like to 
know the official rule so that I run the game right.

Thanks for your time.

-Kel...