现代通信设备的主要几种供电电压为()。
A.±2V
B.24V
C.-48V
D.±15V
参考答案:B, C
肺吸虫患者中枢神经系统病变的发生率为()
A.40%~35%
B.35%~30%
C.25%~30%
D.20%~15%
E.15%~10%
This novel was concerned____the Second World War, while most teenagers are more concerned___ the hero’s love story.
A.with; for
B.with; with
C.for; about
D.about; with