Question

【题目】Our capital, Beijing, ______ on improving the city’s environment in the past three years through various measures.

A. has been workingB. were working

C. workedD. had worked

Answer 1

【答案】A

【解析】

考查动词时态。句意：在过去的三年里，我们的首都北京通过各种措施致力于改善城市环境。由下文“in the past three years”可知，在过去的三年里北京一直致力于改善环境，动作具有延续性，所以应该用现在完成进行时。故选A。