阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。

    My father was a highly educated, intelligent gentleman. He could debate or discuss for hours on almost any topic and hold your 1 in the process. I thought there was nothing he wasn't 2 to do.

    A few days before my younger brother's 7th birthday, Dad planned to assemble（装配）a new  3 as a special birthday surprise. After nearly an hour of  4 the instructions, Dad was still unable to 5 the new bike together. Later he 6 the paper of instructions, 7 up his tool box, and decided to take the bike back to the local toy store and pay extra 8 to have it correctly assembled there. 9 an idea came to him, as he called out to Lovett, the quiet little man who cut our grassland.

    “Lovett, have you ever assembled a boy's bicycle?”

    As Lovett walked towards the bike, Dad handed him the 10 . Lovett handed it back to him, saying, “No, thanks. I can't read. When you can't read, you have to 11 .” Less than 15 minutes later, the new bicycle was 12  assembled, with no 13  parts remaining. Dad shook Lovett's hand, patted him on the back, thanked him, and hid the bike.

    On the night after my brother received his shiny new gift, Dad announced at the family dinner table what had happened several days earlier. He took great 14  in telling it over and over again — he used it as an example of thinking.

    He did not refer to illiteracy（文盲）, but strongly taught us to use our  15  . The joke was on my father,  16  he was able to turn it into a learning tool, and I liked him even more after that incident. I also gained a new  17  for Lovett. To me he had  18  been the old yard man who didn't 19  much, but after that day, he seemed to smile 20  , even walk taller. It's amazing what a real nod of approval can do to lift people up.