As far as novels go, in high school especially, they want you to always recognize symbolism. The term carry, as far as we know in the English language, is something you basically lift and hold. But in this instance, especially with this title, it has two meanings. It is a metaphor for all the bad things that the solider carry with him after the war. It's all the emotional baggage from everything they see, all the friends they lost, all the fear they had, etc. It also means the literal form of carrying other soldiers who have fallen and need help. You can really answer this anyway you want as long as you get the purpose that carry is. a metaphor.
