Obedience is the first duty of a soldier军人以服从命令为天职。 Observation is the best teacher.观察是最好的老师。 Offense is the best defense.进攻是最好的防御。 Old friends and old wines are best.陈酒味醇，老友情深。 Old sin makes new shame.一失足成千古恨。 Once a man and twice a child.一次老，两次小。 Once a thief, always a thief.偷盗一次，做贼一世。 Once bitten, twice shy.一朝被蛇...
