单选题 No sooner had Mrs. Smith entered the kitchen ______ a knock at the door.
  • A. did she hear
  • B. than she heard
  • C. then she heard
  • D. when she heard
【正确答案】 B
【答案解析】[解析] 此题测试No sooner…than…这个句型。意思是“一……就……”。因此，答案是B)。