Please try to solve the following question about logic: suppose I have a cabbage, a goat and a lion, and I need to get them across a river. I have a boat that can only carry myself and a single other item (cabbage, goat or lion). I am not allowed to leave the cabbage and goat alone together, whether on the boat or at either side of the river bank, and I am not allowed to leave the lion and goat alone together, whether on the boat or at either side of the river bank. How can I safely get all three across the river?