A real story...Courage

This is a real story. The setting of the story is not mentioned.

A boy whose parents have passed away lived together with his only sister. She is his only close relative. Therefore the boy considered her sister was more important than himself. He loved her sister much more than loving himself.

Unfortunately, the sister was infected a kind of disease. She needed other's blood to save her life. Although the doctor promised them not to collect money from the operation, they still couldn't afford the expense of blood. The expense of blood was too high for the young boy. He really needed the blood to save her sister's life or else she would die.

As the only close relative of the girl, the boy's blood group was similar to his sister's. His sister's life was really on him at that moment. He was the key of survival for his sister. Yet, did the boy really have the courage to bear the pain during the blood transferring process? He started to hesitate.

After thinking for a while, the 10 years-old boy promised to donate his blood to his sister.

During the process of blood transferring, the boy didn't look to fear. He just kept smiling to his beloved sister. Once the process finished, he asked the doctor: may i know for how long i still can be alive?

The doctor was stunned with this question. He knew what the young boy was thinking about. In the boy's thought: he would die if he transfered blood to his sister. However he still had the courage to transfer his blood to his sister. At that moment when the boy made up his mind to transfer his blood, he was ready to sacrifice himself to save his sister. The courage was rather seen even on adults. Yet, it came from a 10 years-old boy.

The doctor held the boy's hand tightly and said: Don't worry about that, nobody will die after transferring blood to others.

The boy stared at the doctor surprisingly and said: Really? So for how long can i live?

The doctor replied him with a warm smile: You are very healthy. I think you can live for 100 years!

The boy suddenly became serious and showed his hand, the hand which was used to transfer blood just now to the doctor and said:Now i need you to distribute my blood equally for us so that
we both can live for 50 years!

Everyone cried after hearing that word. They were touched by the courage of the boy. They also witnessed the faithful side of mankind through the sincere promise of the children.