雨后的天空出现彩虹，这是由于（  ）

    When I was a child, my father had to do three jobs for a family of seven. Every time I saw him come back late, looking 1 I promised myself that someday I would show my 2 to my father for what he had done.

    Over the next twenty years, my father worked hard to 3our big family and suffered a lot from a heart problem. One morning, my father's old car broke down and he asked me to 4him up after his medical examination. He had 5 refused when I offered to replace (取代) his old car. He said that he did not want something that he couldn't pay6.

    7he stepped out of the doctor's office, he looked serious. We drove in silence and he made me promise to keep the medical report as a8. I did this with a heavy heart.

    At that time, I was 9a new car. I asked my father to go with me to pick10out. When I started talking with the salesman, I noticed my father11a brown car. I12chose a white car. My father took one final look at the brown car and seemed kind of 13before leaving. I heard him muttering (嘀咕) to himself, “14like that car. Wish I could 15it.”

    Several days later, I asked my father if he could go with me to pick up16new car. As we arrived, the salesman17him a key to a new car - the brown one - and18that it was for him, from me. My father looked at me in great19 I told him it was my childhood20and smiled at this man, who had given up everything for his family.