She decided to have a physical checkup as soon as she finished _

She decided to have a physical checkup as soon as she finished ______.
A、what she did
B、what she had done
C、what she would do
D、what she was doing
【正确答案】：D
【题目解析】：分析句子结构并结合选项可知，finish之后为what引导的宾语从句。根据句意可知，从句应用过去进行时，表示过去某一时刻或某段时间内正在进行的动作，故选D。