### Chinese: 大部分女孩子会在13-15岁期间的某一天突然经历第一次例假，在50岁左右闭经。
### English: Most girls will suddenly experience their first <v>regular holiday</v> on a certain day between the ages of 13 and 15, and amenorrhea around the age of 50.

### Improved English: Most girls will get their first period between 13 to15 years old, and have amenorrhea around 50.
