单选题 The committee ______ the problem for a whole afternoon but they have not yet reached an agreement.
  • A. has discussed
  • B. has been discussing
  • C. are discussing
  • D. have been discussing


【正确答案】 D
【答案解析】committee是集合名词，后面的谓语用复数．现在完成进行时照应后文“they have not yet reached an agreement”。