### Chinese: 卫生巾最好两三个小时更换一次，不然容易滋生细菌，除去睡眠时间，最坏的情况是一天更换6次，每月7天，那就是42片，如果加上提前准备的份可能有50片，并不是每个月用一片。
### English: Sanitary napkins should be replaced once every two or three hours, otherwise it is easy to breed bacteria. Apart from sleep time, the worst case is to replace them six times a day, seven days a month, that is, 42 tablets. If you add the portions prepared in advance, there may be 50 tablets, not one tablet per month.

### Improved English: It is best to replace sanitary pads every two or three hours, otherwise it is easy to breed bacteria; apart from sleep time, the worst case is to replace them six times a day, seven days a month, and that is 42 pieces; if you add the ones prepared in advance, there may be 50 pieces, not just one piece every month.
