绝缘子用来使导线和杆塔之间保持（）状态。
A.稳定；
B.平衡；
C.绝缘；
D.连接。
参考答案：C
缓冲器的设置可增加冲击。
— Lily and Lucy look the same.
— That's true. Sometimes it is really difficult to _____ them apart. [ ]
A. tell
B. say
C. talk
D. speak
