题目

Liao Fan, a Chinese actor, finally got to know      real success tastes like when he won the prize for Best Actor at the 64th Berlin film festival．      A．when               B．how               C．what               D．where 答案：C如图所示，开关S闭合，螺线管的右端是    极，要使它的磁性增强，可将滑片P向    端移动．