请编辑以下文章，排除其中的所有连续空格和行末空格，将所有标点符号标准化： 
Once upon a time ,there lived a rabbit in a forest .The rabbit was very proud of his speed .One day ,he got into a fight with a tortoise who claimed to be faster .So ,they decided to have a race .The rabit ran very fast for a while ,but he tired soon and fell asleep under a tree .The tortoise walked slowly ,but steadily and finally finished the race first .
Once upon a time, there lived a rabbit in a forest. The rabbit was very proud of his speed. One day, he got into a fight with a tortoise who claimed to be faster. So, they decided to have a race. The rabbit ran very fast for a while, but he tired soon and fell asleep under a tree. The tortoise walked slowly, but steadily and finally finished the race first.