12个数字两两组合一共多少种情况

简介：A good example is that if you have someone you like in this city, it is not too difficult to meet them. After all, there are rail transits everywhere in the city. Although it takes a certain amount of time to cross the geographical distance between the cities, if you don’t want to meet them, If you are alone, then even if you live next door, you will never have to see him.