Who knows the meaning of these three poems written by Du Fu?

Seventh, the recruiter told him about building a city and guarding it on the mountain in cold weather. It was snowing, the army entered the mountains, and the surrounding environment was bad. It's far from the Central Plains. When can I go back? It seems impossible to really fight.

Eighth: the recruiter tells the story of his first meritorious service and his attitude towards it. The first two sentences are about the scene of war, and the third sentence is about meritorious service.

Nine: The recruiter tells his experience of fighting in the army for more than ten years. The first sentence is simple. The second sentence says that people value the occasional meritorious service, but I want to say that I am ashamed to be like them. There are still wars and dangers in this country. As a gentleman, I should realize my ambition to pacify the quartet. How can I shirk my responsibility to myself?

The general idea is similar. I only found a general statement from my dictionary of Tang poetry, nothing more specific. I translated it word for word myself.