这些老兵们即使在和平年代仍然保持着兄弟般的情谊，因为他们曾是并肩作战的战友。

These veterans still maintain a brotherly bond in peacetime, as they were ___brothers-in-arms during the war.

这些士兵在战场上并肩作战多年，早已成为生死与共的战友。

After years of fighting side by side on the battlefield, these soldiers have become true ___brothers-in-arms.