Du Fu
The drums of the defenders cut off people's communication, and a lonely goose was singing in autumn in the frontier.
The dew turns to frost tonight, and the moonlight at home is bright!
Brothers are scattered, and no one can ask about life and death.
Letters sent to Luoyang city are often not delivered, and wars often do not stop.
In the eyes of homesick people, the moon in my hometown is particularly bright; The two brothers haven't heard from them for a long time because they left Chaos, and they can't even write a letter. Nostalgia is gradual.
"He knows that the dew tonight will be frost" means that the season at that time is really white dew, and it also gives the author a sense of desolation and chill, which means that "the white dew on the leaves was discovered from tonight" (in fact, the explanation of this sentence is not very important, just understand the artistic conception of expression), "and the moon in the sky is still relatively bright in my hometown" (this sentence is particularly critical, obviously it is the same bright moon, but the author stubbornly thinks it is.