单选题 Ever since the Smiths moved to the suburbs a year ago, they ______ better health.
A. are enjoying B. have been enjoying
C. could have enjoyed D. had enjoyed

【正确答案】 B
【答案解析】[解析] ever since表示自过去的某个时间直到现在为止，所以谓语需用完成时态。如果过程已经结束，需用现在完成时；如果过程尚未结束，需用现在完成进行时。