单选题 The discussion was so prolonged and exhausting that ______ the speakers stopped for refreshments.
  • A. at large
  • B. at intervals
  • C. at ease
  • D. at random
【正确答案】 B
【答案解析】[解析] 各项的意思为：at intervals不时，时时。at large逍遥法外，未被捕获；at ease自在，合适；at random任意，随机。所以，本题选B。