Well, that is to say, if I go from A to E, I have to pass through B, C and D on the way. Then, Kunming is now building subways everywhere. If many cars go to E, the traffic pressure on the repaired road section will be too great. Therefore, it is stipulated that some cars should turn around and go to A on the way or near the terminal! So, if you want to reach the terminal, you can't take a u-turn car!