励磁小电流试验是哪种方式：（）
A.电压；
B.励磁电流；
C.无功；
D.控制角。
参考答案：D
Most of the differences among companies with respect to quality of earnings are addressed when companies are compared using:（）
A. price to earnings ratios.
B. price to cash flow ratios.
C. both price to earnings ratios and price to cash flow ratios.
反映右室后负荷的最佳参数是（）
A.平均肺动脉压
B.肺循环总阻力
C.肺血管阻力
D.外周血管阻力
E.动脉平均压
