填空题
Last summer I learnt ride a bicycle. At first, I was 75. ______ unable to control its direction. Sometimes I fall to 76. ______ the right or to the left. I worried to ask his father 77. ______ impatiently how I could fide straight, so he didn't78. ______ answer me directly. Instead, he takes me to side of the79. ______ street. "Can you find any bike track is really straight?"80. ______ asked my father. I watched more careful and shook my 81. ______ head. "No," he said, "in fact, neither of the tracks is 82. ______ always straight. But just by correct the direction 83. ______ every now and then, you had already gone forward." 84. ______