Tiancheng*haicheng

Grandpa said this: "You guard the tower for me. If anything happens, ring this bell. Don't fall asleep." After that, he went downstairs. Ash knew he was going to bed. Asi also knew that grandpa was sleeping now so that he would be energetic to fish with everyone tomorrow, so that he could earn more money. Since his parents died in the tsunami, Assi has relied on his grandfather to earn money to support his education. Axi is now twelve years old, and he wants to help his grandfather do something. Grandpa only occasionally let him guard the tower during school holidays. Grandpa is the night watchman on the Haicheng watchtower. There are four watchtowers at the four corners of Haicheng, and people are on duty in shifts day and night. Night watch is actually a very easy job. At night, the engines stopped and the entire city floated quietly on the sea, almost motionless. Haicheng is so big that it cannot feel ordinary wind and waves. What grandpa has to do at night is to keep watch in the hut on the top of the tower to see if any other sea cities or ships are coming here. That kind of opportunity is very rare. If there is, he will send a light signal to the other party: "Don't get too close to avoid collision." And notify the officer on duty in the city for fear of meeting pirates. Conception: