As for how to repair the engine, it mainly depends on the wear and tear of the engine. The light piston ring can be replaced, and the heavy piston and piston ring can be replaced at the same time, which is particularly serious and needs to be blocked. If the engine burns oil slightly, frequent oil addition can last for a while. If the wear is serious, it can't be repaired, and the loss will be even greater in the future.
The engine has run 120000 km, so it's time for overhaul.