I believe the answer is: <span>purchasing days determined by license plate numbers
At that time, the Gasoline reserve was in an extremely high demand while its production was still extremely limited. To handle this, the government divide the purchasing right based on the end number of license plate. (odd numbers could buy at day X while even numbers could buy it at day Z) </span>
<span>This is the continuity and stage theory. In this viewpoint, development takes place gradually, with the person getting to a certain level of mastery, staying there for a period, then having breakthroughs that take them to another, higher level of accomplishment. Only after having learned the one tactic does the person become able to learn the next, more complex, step.</span>
