I can't go back to my hometown. If you have seen my robot girlfriend, you can understand this sentence well. My hometown, with the passage of time, has changed a lot, and it is not what I remember. Maybe one day, when you come to your hometown and see that you can't find the fields where you played as a child, and you can't hear grandma's kind exhortation, you will have such a feeling that you can't go back, and the warm and lovely hometown in your memory can't go back anymore.
"If you can't reach it, it's far", far, forever! From the countryside to the city, what you see is that the capital is far away. When you arrive in Beijing, you see that the United States is far away, far away and always ahead. What you step on can no longer be called far. So, the distance refers to the place where you haven't arrived yet. Then the distance will never arrive, because it is not called distance when it arrives!