Many years ago, when I worked as a volunteer at Stanford Hospital, I got to know a little girl (name) Liz who was suffering from a rare and serious disease. Her only chance of(recover) appeared to be a blood transfusion（输血）from her 5-year-old brother had miraculously survived the same disease and had developed the antibodies needed to fight the (ill).

    The doctor(explain) the situation to her little brother, and asked the boy if he would be willing to give his blood to his sister. I saw him hesitate for a moment before taking a deep breath and saying, “Yes, I'll do it  it can save Liz.”

    As the transfusion progressed, he lay in bed next to his sistersmiled, as we all did(see) the color returning to her cheeks. Then(he) face grew pale and his smile faded. He looked up at the doctor and asked with a trembling voice, “Will I start to die right away?”

    Being young, the boy had(understand) the doctor; he thought he was going to have to give his sister all of his blood.