Driving on the highway is a narrow road that can only accommodate one car. At this time, another car came to the front. They were halfway there. No one wanted to go back, so they didn't give in and fell into endless waiting.

Mutual exclusion: Only one car can occupy a space in the roadway .Hold and wait a car holding their place is waiting to acquire other place held by other cars.No preempt: A car cannot be removed from itsposion in the roadway after other cas remove.Cicuar wat:Each ca is waitingfor a subsequent car to advance.Thecircular wait.

One of them takes a step back and stipulates that when there are vehicles entering the section, other vehicles belong to the waiting state.