In "The Old Man at the Bridge," Hemingway uses a lot of metaphor and symbols. Explain them.

Animal symbolism is important in this short story. The old man is very concerned for the fate of his animals, which he has been forced to leave behind in a dangerous war zone. They symbolize the victims of war: innocents who have done nothing but nevertheless have to suffer for evils perpetrated by others that they, the animals, can't begin to understand.
The specific animals are important symbols too. The cat symbolizes those who can get away and survive, (if not happily) by their wits. The goats, who cannot so easily get away, represent the literal scapegoats: those that have to pay for the crimes of others.
Easter Sunday is a symbolic date too, as it commemorates the resurrection of Jesus, another innocent scapegoat who suffered violence. Here, however, Easter is not a time of resurrection but of continued violence and hate.
The old man's steel rimmed spectacles are a symbol of his ability to see more clearly to the heart of war's evil than the people around him.
A metaphor is a comparison between two seemingly dissimilar things, and the animals also function as metaphors in the story: they are like the innocent humans who are victims of war. The dust is a metaphor for the weariness everyone feels about the seemingly endless warfare.