单选题 The magician picked several people ______ from the spectators and asked them to help him with the performance.
  • A. by chance
  • B. at random
  • C. on occasion
  • D. on average
【正确答案】 B
【答案解析】at random“随便，随意地，胡乱地”；A项by chance“偶然地，意外地”；C项 on occasion“不时地，间或”：D项on average“平均”。