第二节：用括号里所给动词的正确形式填空（共10小题, 每小题1分, 满分10分）
81. While I was busy _________ (prepare) for the final examination, I still work out every day.
82. She used to _________ (play) cards after supper, but now she is used to _________ (take) a walk.
83. With everything she needed _________ (buy), the old lady took a taxi home.
