What Am I Riddles

Question: I can't go left, I can't go right. I am forever stuck in a building over three stories high. What am I?

Question: Rarely touched but often held If you have wit, you'll use me well What am I?

Question: Look at my face, I am somebody. look at my back, i am nobody. What am I?

Question: What has 3 feet but cannot walk?

Question: I'm written with two letters, said with one and seen with two.What am I?