Good Riddles

Question: I can be one, I can be two. I can be Open, Closed, Empty or Full. I can be Bare, but never a Bear. What AM I??

Question: in all of written history I won't show up at the end of a sentence but I will be there in the end . . .

Question: Act in my name, and thus remove me. What am I?

Question: Say you roll five dice and get a one, a two, a three, a four, and a five. Your sum would be six. Rolling all threes would give ten. Rolling a two, four, two, four, and six would be zero. Rolling a two, three, four, five, and six would be six.

What would you get if you roll a three, a four, a one, a five, and a four?

Question: What's strong enough to smash a ship but is still afraid of the light?