单选题 ______ the train station, he waved again and again to me.
  • [A] Leaved
  • [B] To leave
  • [C] Lea
  • [D] When leaving


【正确答案】 D
【答案解析】强调与谓语动词的动作同时发生时，现在分词前可用连词when。答案为D。