置闰

例句：

1. 1. The calendar is set to observe thesolar year, which includes both theGregorian and the Julian calendars.
   日历被设置为观察太阳年，包括格里高利历和儒略历。
2. 2. The decisionto add a leap year for thecentennial celebration was made during the meeting.
   决定在百年庆典期间增加一个闰年是在会议期间做出的。
3. 3. The calendarsystem has evolved over time to accommodate thechanging seasons and the need for more accuratepredictions.
   日历系统随着季节的变化和更准确预测的需求而不断演变。