原子吸收分光光度计的分光系统的作用主要是调节光的强度，使进入检测器的光量合适。( )
参考答案：错
_____ John won a gold medal in the English competition really excited his family.
A．That
B．when
C．which
D．what
电火花表面强化有何特点？与电火花成形加工有何区别？
