calendar stone

例句：

1. 1. The calendar stone in the museum is a fascinating exhibit.
   博物馆里的日历石是一个引人入胜的展品。
2. 2.The sundial at the park was made from this type of stone.
   公园里的日晷是用这种石头制成的。
3. 3. The calendar stone has been used for centuries to mark the passage of time.
   日历石被用来标记时间的流逝，已经有好几个世纪了。