数控加工对刀具有哪些要求？
参考答案：
与普通机床切削相比，数控机床对刀具的要求更高。不仅要求精度高、刚度好、耐用度高、而且要求尺寸稳定、安装调整方便等。
Maria has written two novels, both of _____ have been made into television series.
A．them
B．that
C．which
D．what
高压熔断器在电路中的作用原理如何？
