was ALF filmed before a live studio audience? the set looks like a classic sitcom- set.

The ALF TV series was not taped with a live audience. Due to extreme attention to detail and difficulty of actors interaction with the ALF puppet, taping often took several 16 hour days.
The ALF set itself was most unique in that it was raised 4 foot off the floor, so that the puppeters could move about placing ALF wherever he needed to be in the various scenes.
Mike

thanks for u'r interesting answer. wow I think working with ALF was very extreme and strenous. I admire the actors, it's so sad that nobody is on TV anymore.