The phrase 'this yo-yoing' in the 1st paragraph refers to______. A．the percentage of Medicare patients in hospitals B．the huge cost of Medicare for patients in hospitals C．the better care Medicare patients will benefit from D．high rates of readmission of patients into hospitals
A. A．the B.the C.the D.high
【参考答案】
D 根据第一段上下文，“thisyo-yoing”指该段第一句所说的“在所有享受医疗保险的病人中．出院后……重返......