The food issue is not only an economic issue, but also a political one, related to the long-term stability of the country.
现在数学家面临的最大问题可能是黎曼假设。
Stories you read when you're the right age never quite leave you. You may forget who wrote them or what the story was called. Sometimes you'll forget precisely what happened, but if a story touches you it will stay with you, haunting the places in your mind that you rarely ever visit.