绝缘栅双极晶体管的开关速度（）电力晶体管。
A、低于
B、等于
C、稍高于
D、明显高于
参考答案：D
The professor could hardly find enough grounds on which to base his arguments ______ the new theory.
A．in honor of
B．in favor of
C．in case of
D．in memory of
PLC（电力线通信）的关键技术是什么？
