ruby knife

例句：

1. 1.This ruby knife is the best choice for cutting delicate fruits.
   这把红宝石刀是切割娇嫩水果的最佳选择。
2. 2. The old man used to carry a ruby knife in his pocket.
   那位老人过去常把一把红宝石刀放在口袋里。
3. 3. She admired the beauty of the ruby knife and its sharpness.
   她欣赏那把红宝石刀的美丽和锋利。