诗人说,地球是宇宙中的一颗蓝宝石;宇宙学者说,地球可以没有人类,但人类决不能没有地球;天文学家说,地球是一颗围绕恒星运转的中等大小的行星;环保主义者说,地球是我们的母亲;生物学家说,地球是目前所知唯一的生命家园;宇航员说,地球在宇宙是那样的小,小得像餐桌上的一颗饭粒,用抹布一抹就可拂去。 The poet says the earth is a sapphire in the universe; cosmologists say there can be no human being on earth, but mankind must never have no earth; astronomers say the earth is a medium-sized planet that runs around a star; and environmentalists say, The Earth is our mother; biologists say the Earth is the only homeland known to date; the astronauts say the Earth is so small in the universe that it looks like a rice grain on a table that can be brushed with a rag .