单选题 Ever since he ______ his job, Allen has been much happier than before.
  • [A] has changed
  • [B] had changed
  • [C] changed
  • [D] changes


【正确答案】 C
【答案解析】[精解] 本题考查动词时态。ever since的意思是“从那时到现在”。一般情况下，从句谓语动词用一般过去时，而主句的谓语动词用现在完成时。即前面的change应该用一般过去时。所以本题的正确答案为C。