单选题 She had just finished her homework ______ her mother asked her to practice playing the piano yesterday.
  • A. while
  • B. when
  • C. after
  • D. since
【正确答案】 B
【答案解析】[解析] when在本句中作并列连词，意为：and at that time。while作并列连词，表示“对比转折”；after为从属连词或介词，意为“在…之后”；since“自从…时候，既然…”。