单选题 Heart ______ is much more common these days than it was even ten years ago.
A. surgery B. surgeon
C. work D. circulation

【正确答案】 A
【答案解析】[解析] 词义辨析
A．surgery外科(学)，(外科)手术；B．surgeon外科医生；C．work工作，职业； D．circulation循环，流通；因此A为答案。