blood-brother

例句：

1. 1. He was always there for his blood-brother during difficult times.
   在困难时期他总是他的兄弟。
2. 2. They were both blood-brothers and shared a deep bond.
   他们都是血兄弟，有着深厚的关系。
3. 3. The two brothers are blood-brothers, and they have been inseparable since childhood.
   这两个兄弟是血兄弟，从童年起就形影不离。