大数定位之层进式阶梯倍投法

简介：Of course, some people with romantic feelings prefer to write letters and have the letters delivered by the post office. Sometimes, if it is fast, it will arrive in a few days. If it is full, it will be ten days and a half. It is also a good idea at that time to be able to receive letters from people from far away. It shows that he is a very popular person.