Good Riddles

Question: there are 3 houses. a brown house a green house and white house. if the green house is in front of the brown house. and the brown house is in the back of the green house, Where is the white house?

Question: Like a middle pillar I stand among 6, all 9 of my characters make me the largest to exist.

Question: Keys! keys! So many keys, When F is involved The key note is _ ?

Question: When people cut me, I do not bleed. They use me, but then they leave. I die, but then revive. I change my appearance as time goes by. What am I?

Question: At first I'm in pieces, but you build me and I carry you, at night when your tired or sleepy or even drunk, what am I?