According to the size of cigarette cases and people's habits, 20 sticks of ordinary cigarettes are just right, which has gradually become an industry regulation, and it is not allowed to pack more or less. It is convenient to set and compare the prices of various cigarettes, with no more than one box per day and only 20 cigarettes per box to remind people to smoke less.

Another romantic saying is that one loves you, one waits, one expects, one yearns, one fantasizes, one is sad, one is happy, one is sad, one is lonely, one is lonely, one pretends, one is strong, one is weak, one misses, one is silent, one is crying, and one is sad.

From a realistic point of view, there were no rules in the past It was not until the emergence of filter-tip cigarettes that a box of 20 cigarettes was formed. This is because the filter tip of cigarette is made of polypropylene tow for cigarette, which is easy to absorb moisture. When the paper cigarette case is not wrapped with plastic cellophane, the amount of polypropylene tow put together by 20 cigarettes will not make the tobacco wet in a short time, which is close to the limit. It has been used ever since.