【简答题】What is the sky? Where is it? How high is it? What lies above it? These questions are difficult to answer, aren’t they? Is the sky blue? No, the sky has no colour. Is the sky full of air? Yes, we know...
【简答题】What is the sky(天空)? Where is it? How high is it? What lies above it? These questions are hard to answer, aren’t they? Is the sky blue? The sky has no color. We know that there is air around the world...