What Am I Riddles

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

Question: I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody.

What am I?

Question: Everyone asks for me but yet everyone hates to face me ,for someone I am agony for others I am relief! Who am I?

Question: What demands an answer, but asks no question?

Question: Something different to show every week, but I'm still the same place.
If you're eating it's probably butter that you taste.

What am I?