Good Riddles

Question: There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?

Question: What am I?

Question: What is the only question you can't answer yes to?

Question: Railroad crossing without any cars. Can you spell that without any R's?

Question: I stare at you, you stare at me.I have three eyes, yet can't see.Every time I blink, I give you commands.You do as you are told, with your feet and hands.What am I?