Strategic Bombers

I don't use strategic bombers, but i want to understand them better so that i can defend against them...

When i have a ground unit stationed in a city center, can someone attack a city of mine with a stack of just strategic bombers, and do damage to my buildings?

If so, how does that work? For example, Axis Level 1 strategic bombers do 1.5 damage to ground units and 17 damage to buildings. If an enemy attacks my city with one Strategic bomber, and my city has an AA unit in the city center, does the strategic bomber do 1.5 damage to the ground unit...or does it do 17 damage to the building??