A型显示超声波探伤仪，为使反射回波由下向上显示在荧光屏上，视频放大信号应接在（）。
参考答案：垂直偏转板
Which of the following choices indicates that your project is 9% under budget ？（）
A．The cumulative AC was 100, and the cumulative EV was 110
B．The cumulative PV was 100, and the cumulative AC was 110
C．The cumulative AC was 110, and the cumulative EV was 100
D．The cumulative EV was 100, and the cumulative PV was 110
评价临床效果的主要指标是（）。
A.对照组的依从性
B.试验组的依从性
C.病死率
D.有效率
E.失访率
