自然伽马仪器电缆驱动器的作用是对脉冲信号进行功率放大和实现与电缆的（）。
参考答案：阻抗匹配
Zhang Guorong’s singing career _________ about over 20 years. It was his ________
appearance at singing in public.
A．last ;last
B．lasted for; last
C．lasted; lasted
D．lasted for; lasted
前牙3/4冠的邻面沟位于
A．邻面片切面的舌1/3
B．邻面片切面的中1/3
C．邻面片切面的唇1/3
D．邻面片切面的中1/3与舌1/3的交界处
E．邻面片切面的中1/3与唇1/3的交界处
