单选题 When once you have caught the disease, you are immune from it for the rest of your life.
  • A. free
  • B. busy
  • C. calm
  • D. impatient


【正确答案】 A
【答案解析】immune“免疫的”；free“免于”；busy“忙于”；calm“安静”；impatient“不耐烦”。