传声器的动态范围反映了传声器的工作频率范围。( )
参考答案:错
与产生X线强度无关的因素是()
A.靶物质
B.管电压
C.管电流
D.高真空度
E.高压波形
China is very different ____ Canada in culture.[ ]
A. between
B. from
C. with
D. among