知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。Early 70s scifi novel about underground people, caste is decided by the color of one's poncho, and everybody eats mouldy grainBe Your self: Authenticity is vital to forming significant friendships. Be you, share your pursuits, and hunt for people wh