Choose One

Question: There're two people in front of you: your friend and an imposter looking exactly like your friend. There's no way to determine who is who by asking questions, they know the same information about you. You have only one bullet in your gun. If you kill or injure the imposter, you and your friend will be saved, If you're wrong, he'll kill you immediately. How will you know?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: What can be broken but never forgotten?

Question: Which thing that comes once in a year, twice in a week?

Question: You are trying to get your chicken, fox, and wheat to the barn. However, the barn is on the other side of the river. You are on a boat and can only transport one animal or wheat at a time. You must choose carefully not to leave the wrong two together, though. It's either the fox will eat the chicken or the chicken will eat the wheat. How do you take each thing across safely?

Question: During what month do people sleep the least?