《资治通鉴·秦纪·秦纪一》
俗话说： 太阳升到中天就要偏斜而西，月亮圆满了即会渐见亏缺。 
语曰： 日中则移，月满则亏。 
As the saying goes: when the sun rises to the highest point in the sky, it will start to decline; when the moon is full, it will begin to wane.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 语曰： 日中则移，月满则亏。  [/INST] As the saying goes: when the sun rises to the highest point in the sky, it will start to decline; when the moon is full, it will begin to wane.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 语曰： 日中则移，月满则亏。
user
As the saying goes: when the sun rises to the highest point in the sky, it will start to decline; when the moon is full, it will begin to wane.
assistant