第15题: [单项选择]GPON最小带宽效率可达() A. 0.92 B. 0.72 C. 0.9 D. 0.89 参考答案:A
第16题: [单项选择]Though she could hardly make ends meet herself, she managed to save______ she could out of her slim salary to help her brother to go to school. A. how little money B. such little money C. so little money D. what little money 参考答案:D 答案解析:what在这里是关系形容词,表示“所……的”,“尽可能多的”。what little money she could (save) =that little money which she could
第17题: [单项选择]妊娠期母体心脏负荷最重的时间是妊娠() A. 24~28周 B. 30~32周 C. 32~34周 D. 34~36周 E. 36~40周 参考答案:C 答案解析:循环血容量于妊娠6周起开始增加,至妊娠32~34周达高峰,约增加35%,平均约增加1500ml,维持此水平直至分娩。